Akosombo Dam - Design

Design

The dam is a 660 m (2,170 ft) long and 114 m (374 ft) high rock-fill embankment dam. It has a base width of 366 m (1,201 ft) and a structural volume of 7,900,000 m3 (10,300,000 cu yd). The reservoir created by the dam, Lake Volta, has a capacity of 148 km3 (120,000,000 acre·ft) and a surface area of 8,502 km2 (3,283 sq mi). The lake is 400 km2 (150 sq mi) long. Maximum lake level is 84.73 m (278.0 ft) and minimum is 73.15 m (240.0 ft). On the east side of the dam are two adjacent spillways that can discharge approximately 34,000 m3/s (1,200,000 cu ft/s) of water. Each spillway contains six 11.5 m (38 ft) wide and 13.7 m (45 ft) tall steel floodgates. The dam's power plant contains six 170 MW Francis turbines. Each turbine is supplied with water via a 112–116 m (367–381 ft) long and 7.2 m (24 ft) diameter penstock with a maximum of 68.8 m (226 ft) of hydraulic head afforded.