Longtan Dam
Longtan Dam is a large roller-compacted concrete (RCC) gravity dam on the Hongshui River in Tian'e County of the Guangxi Zhuang Autonomous Region, China, a tributary of the Xi River and the Pearl River. The dam is 216.2 m (709.3 ft) high and 849 m (2,785 ft) long; it is the tallest of its type in the world. The dam is intended for hydroelectric power production, flood control and navigation. The dam contains seven surface spillways, two bottom outlets and an underground power station.

Formal construction of Longtan Dam began on the project July 1, 2001 and the river was diverted by November 2003. A total of 20,000,000 m3 (706,293,334 cu ft) of material were excavated from the dam site. Impounding of the 27,270,000,000 m3 (22,108,149 acre·ft) reservoir began in 2006 and the dam's first of three operational hydroelectric generating units was testing May 2007. In 2009, the last generator became operational and the installed capacity increased to 6,426 MW, its annual generation is estimated at 18.7 TWh.

Longtan Dam
Official name 龙滩大坝
Country China
Locale Tian'e County, Guangxi
Status In use
Construction began 1990
Opening date 2009
Construction cost US$4.2 billion
Owner(s) Longtan Hydropower Development Co., Ltd.
Dam and spillways
Type of dam Gravity
Height 216.2 m (709 ft)
Length 849 m (2,785 ft)
Volume 7,670,000 m3 (270,863,494 cu ft)
Impounds Hongshui River
Type of spillway Service, controlled
Spillway capacity 27,134 m3/s (958,228 cu ft/s)
Creates Longtan Reservoir
Capacity 27,270,000,000 m3 (22,108,149 acre·ft)
Catchment area 98,500 km2 (38,031 sq mi)
Power station
Commission date 2007-2009
Hydraulic head 179 m (587 ft) (max.)
Turbines 9 × 714 MW
Installed capacity 6,426 MW
Annual generation 18,700 GWh (estimate)