The Dachaoshan Dam (Chinese: 大朝山大坝) is a gravity dam on the Lancang (Mekong) River in Yunnan Province, China. The sole purpose of the dam is hydroelectric power production as it supplies water to a power station containing six 225 MW generators for a total installed capacity of 1,350 MW.
Background
Initial construction preparations on the dam began in 1993 before it was approved ready for construction in 1994. On August 4, 1997, the project was approved for construction commencement and on November 10, 1997, the river was diverted. Between 2001 and 2003, the dam was complete and all six generators went operational.[1]
Design
The dam is a 111 m (364 ft) tall and 460 m (1,509 ft) long gravity dam.[2] It is composed of 1,126,700 m3 (39,789,035 cu ft) of concrete, 756,600 m3 (26,719,077 cu ft) is roller-compacted concrete. The reservoir created by the dam has a capacity of 940,000,000 m3 (762,070 acre⋅ft). To release water downstream, the dam has five 14 m (46 ft) x 17 m (56 ft) crest openings along with three mid-level openings and one bottom flushing outlet. With these openings, the design flood discharge capacity of the dam is 18,000 m3/s (635,664 cu ft/s) while the maximum is 23,500 m3/s (829,895 cu ft/s).[1]
The dam's power station is underground and supplied with water via six 179.5 m (589 ft) long penstocks. Once through the six turbines, the water exits back to the river by means of two tailrace tunnels, one 1,355 m (4,446 ft) long and the other 1,248 m (4,094 ft).[1]
