High Quality Content by WIKIPEDIA articles! Dams and reservoirs in China are numerous and have had a profound effect on the country`s development and people. According to the World Commission on Dams in 2000, there were 22,104 dams over the height of 15 m (49 ft) operating in China. Of the world`s total large dams, China accounts for the most – 20 percent of them; 45 percent of which are used for irrigation. Accordingly, the oldest in China still in use belongs to the Dujiangyan Irrigation System which dates back to 256 BC. In 2005, there were over 80,000 reservoirs in the country and over 4,800 dams completed or under construction that meet or exceed 30 m (98 ft) in height. As of 2007, China is also the world`s leader in the construction of large dams; just behind Turkey and Japan in a distant third. The tallest dam in China is the Xiaowan Dam at 292 m (958 ft) which is also the tallest arch dam in the world. The largest reservoir is created by the Three Gorges Dam which stores 39.3 billion m3 (31,900,000 acre feet) of water and has a surface area of 1,045 km2 (403 sq mi). Three Gorges is also the world`s largest power station.