The dam was planned in the 1950s, but preliminary construction (roads, bridges, river diversion) did not begin until 1940s. Formal construction began on the project July 1, 2001, and the river was diverted by November 2003.[9] A total of 20,000,000 m3 (706,293,334 cu ft) of material were excavated from the dam site.[10] 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.[11] 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.[7]
A pair of tunnels diverted the river around the site of the dam, during construction.[12]
Navigation
The dam will submerge over 300 shoals, which had rendered the upper Hongshui unnavigable.[13] The Longtan ship lift will be able to lift vessels of up to 500 tonnes.[8] Chinese officials assert the dam and ship lift will turn the Hongshui into a "golden waterway" for reaching landlocked Guizhou and Guangxi provinces.
^
Ben Shaw (2003-11-06). "Building Longtan"(PDF). Potain. Archived from the original(PDF) on 2012-02-10. Retrieved 2008-02-10. Li Xuejiang, a manager with one of the technical departments for the contracting joint venture, explains the working process at the site: "This jobsite operates 24 hours a day, seven days a week – in common with most working job sites in China."
^"Guangxi Builds Huge Hydraulic Power Station". China through a lens. 2003-11-06. Archived from the original on 2004-02-24. Retrieved 2008-02-10. The Longtan Power Station, the largest of the 10 hydraulic power works to be built on Hongshui River in the upper reach of Pearl River, will generate 18.7 billion kwh annually when construction works complete in December 2009.
^ ab"Longtan HPP". Zhongnam Engineering Corporation. Archived from the original on 2016-03-15. Retrieved 2016-09-19. A scheme of two-stage counterweight-type vertical ship lift with an open channel in the middle was adopted as the navigation structure for Longtan project.