Will the new Xiluodu hydropower plant helps generate extra energy in China?

The planned Xiluodu Hydropower Plant, the second largest of its type in China after the world's largest concrete dam at Three Gorges, will alleviate the latter's pressure in harnessing the Yangtze River, said a senior project director. China began damming the Jinsha River, the biggest tributary to the Yangtze, in preparation for the Xiluodu plant, which is expected to open in 2015.

"The Xiluodu project will help improve the flood-control capacity along the whole reach of the 3,600-km long Yangtze River," said Fan Qixiang, vice president of China Three Gorges Project, (CTGPC), which is also the builder of the Xiluodu project. Fan said that the completion of the Three Gorges Dam in Yichang, Hubei Province, last year has provided 22.15bn cubic meters in maximum flood holding capacity to safeguard the middle and lower reaches of the Yangtze.

However, the 1,030-km upper portion of the river, the Chuanjiang section, is still vulnerable to flood disasters. The main embankments of the river section can only withstand floods that could occur once in five to 20 years, below China's requirement of dyke strengths that can contain floods that may occur once in 50- 100 years, said Fan.

Xiluodu, located upriver of Chuanjiang, has a designed reservoir capacity of 12.67bn cubic meters, of which 4.65bn cubic meters are for flood control. The reservoir can dam one-third of floods to the Three Gorges in Yichang, which is 770 km away from Xiluodu.

According to research from the Yangtze Water Resources Commission, a simultaneous flood-control effort by the dams of Xiluodu and the Three Gorges could instantly prevent 4bn cubic meters of flood surge from inundating the densely-populated plains in the middle and lower reaches of the Yangtze, where China's economic powerhouses like Shanghai, Nanjing, and Wuhan are located.

The CTGPC said the Three Gorges project contained 6.8bn cubic meters of floodwater in total this summer, when the world's largest dam was first used to control a flood crest. The Three Gorges dam was completed on May 20 last year.

Because of its role, the water level downstream at Shashi, Hubei Province fell from a peak of 42.97 meters to 42.69 meters within hours, avoiding the danger of water rising over the 43-meter danger mark.However, the river's maximum recorded flood crest still pushed water levels in Zhenjiang and Nanjing above warning lines. Nanjing, with a population of almost seven million in eastern Jiangsu Province, has prepared sand, soil, and bags at docks and ferries for possible flooding.

Can the new hydropower plant really help ease floods or is it going to be a disaster?