Longtan Dam is a large roller-compacted concrete

Roller-compacted concrete

Roller-compacted concrete or rolled concrete is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Portland cement. RCC is a mix of cement/fly ash, water, sand, aggregate...

 (RCC) gravity dam on the Hongshui River

Hongshui River

The Hongshui River is a major river in the Guangxi Zhuang Autonomous Region in Southern China. It is one of the main rivers in the basin of the Xi River, which in its turn is one of the main tributaries of the Pearl River....

 in Tian'e County

Tian'e County

Tian'e County is a county of Guangxi, China. It is under the administration of Hechi city.-Economics:* Longtan Dam on the Hongshui River....

 of the Guangxi Zhuang Autonomous Region, China

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

, a tributary of the Xi River and the Pearl River

Pearl River (China)

The Pearl River or less commonly, the "Guangdong River" or "Canton River" etc., , is an extensive river system in southern China. The name Pearl River is usually used as a catchment term to refer to the watersheds of the Xi Jiang , the Bei Jiang , and the Dong Jiang...

. 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

Outlet works

A set of outlet works is a device used to release and regulate water flow from a dam. Such devices usually consist of one or more pipes or tunnels through the embankment of the dam, directing water usually under high pressure to the river downstream...

 and an underground power station

Underground power station

An underground power station is a type of hydroelectric power station constructed by excavating the major components from rock, rather than the more common surface-based construction methods....

.

Construction

Formal construction began on the project July 1, 2001 and the river was diverted by November 2003. A total of 20000000 cubic metre of material were excavated from the dam site. Impounding of the 27270000000 cubic metre 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 , its annual generation is estimated at .