Dworshak Dam is a hydroelectric, concrete gravity dam in Clearwater County, Idaho, United States on the North Fork Clearwater River. The dam is located 4 miles (6 km) northwest of the city of Orofino, and 47 miles (76 km) east of Lewiston. The dam is the highest straight-axis concrete dam in the Western Hemisphere and the 22nd highest dam in the World. Only two other dams in the U.S. exceed it in height.
The hydroelectric plant located at the base of the dam is a 428-foot (130 m) long concrete structure and contains one 346,000 horsepower (hp) and two 142,000 hp turbines that power one 220 megawatt (MW) and two 90 MW generators, respectively, for a total capacity of 400 MW. The rated hydraulic head for the powerhouse is 560 feet (170 m), with a maximum of 632 feet (193 m) when the reservoir is full and a minimum of 417 feet (127 m) required for power generation. Up to 10,500 cubic feet per second (300 m3/s) of water can be released through the power plant at maximum capacity. The overload capacity of the two small units is 103.5 MW and for the large unit is 253.0 MW, for a total of 460 MW. If installed, Units 4, 5 and 6, each with a capacity of 220 MW, would bring the total generating capacity to 1,060 MW, making it one of the largest hydroelectric plants in Idaho.