Statistics (Cubic Feet per Second = CFS; Mean Sea Level = MSL; Kilowatts = Kw; Revolutions per Minute = RPM)
Significant Dates:
- Operating Since: 1962
- Construction Start: 1948
- Closure: August 3, 1958
- Reservoir filling initiated: August 1958
- Reservoir first reached minimum operating pool: April 3, 1962
- Initial Power Generation – First and Last Units: April 1962 – June 1963
Powerplant
- Number of turbines: 7 Francis, 100 rpm
- Max power generation capability: 112,290 KW each, 786,030 KW total
Size
- Ranking: 45th largest reservoir in the world, 4th largest reservoir in the United States
- Length of Dam: 9,300 feet (excluding spillway)
- Damming Height: 200 feet (low water to maximum operating pool)
- Maximum Height: 245 feet
- Maximum width at base: 3,500 feet (total)
- Maximum width at base: 1,500 feet (without berms)
- Elevation at crest of dam: 1,660 feet msl
- Spillway crest: 1,620 ft msl
Construction
- Abutment formations (under dam & embankment): Pierre shale
- Type of Fill: Rolled-earth fill & shale berms
- Amount of Fill: 92,000,000 cubic yards
- Amount of Concrete: 1,045,000 cubic yards
Spillway
- Location: Right bank - remote
- Width: 456 feet gated
- Number of gates: 8
- Dimension of gates: 50-foot x 23.5-foot tainter gates
- Design discharge capacity: 304,000 cfs at 1,644.4 feet msl pool elevation
- Discharge capacity at maximum operating pool: 80,000 cfs at 1,620 feet msl
- Top of Spillway Gates (closed): 1,620 feet msl
Intake structures
- Number: 7 power intake structures
- Size: 24-foot diameter
- Length: 3,280 to 4,005 feet long
Outlet works
- Number: 6
- Size: 19.75-foot diameter
- Length: 3,496 to 3,659 feet long
- Release capacity: 18,500 CFS/conduit or total 111,000 CFS
Lake/Reservoir
- Upstream Drainage: 62,090 square miles
- Tributaries: Missouri River, Cheyenne River, Moreau River, Grand River
- Shoreline length: 2,250 miles at 1,607.5 feet msl
- Length of full reservoir: 231 miles
- Surface acres: 310,000 at 1607.5 feet msl
- Storage capacity: 23,137,000 acre-feet
- Maximum depth: 205 feet
- Annual Flood Ctrl & Multi-Use Zone (Elevation): 1,607.5 feet msl – 1,617 feet msl
- Exclusive Flood Ctrl Zone (Elevation): 1,617 feet msl – 1,620 feet msl
- Record Pool Elevation (Date): 1,619.7.6 feet msl (June 26, 2011)
- Record: 160,300 cfs (Mid June, 2011)