Three Gorges Dam, China

The Three Gorges Dam (simplified Chinese: 长江三峡大坝; traditional Chinese:  長江三峽大壩 ; pinyin: Chángjiāng Sānxiá Dàbà) is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in the Yiling District of Yichang, in Hubei province, China. The Three Gorges Dam is the world’s largest power station in terms of installed capacity (20,300 MW) but is second to Itaipu Dam with regards to the generation of electricity annually.

Three Gorges Dam construction

The dam body was completed in 2006. Except for a ship lift, the originally planned components of the project were completed on October 30, 2008, when the 26th turbine in the shore plant began commercial operation. Each turbine has a capacity of 700 MW. Six additional turbines in the underground power plant are not expected to become fully operational until mid-2011. Coupling the dam's thirty-two main turbines with two smaller generators (50 MW each) to power the plant itself, the total electric generating capacity of the dam will eventually reach 22,500 MW.

As well as producing electricity, the dam increases the Yangtze River's shipping capacity, and reduces the potential for floods downstream by providing flood storage space. The Chinese government regards the project as a historic engineering, social and economic success, with the design of state-of-the-art large turbines, and a move toward limiting greenhouse gas emissions. However, the dam flooded archaeological and cultural sites and displaced some 1.3 million people, and is causing significant ecological changes, including an increased risk of landslides. The dam has been a controversial topic both in China and abroad.

History

A large dam across the Yangtze River was originally envisioned by Sun Yat-sen in The International Development of China, in 1919. He stated that a dam capable of generating 30 million horsepower (22 GW) was possible downstream of the Three Gorges. In 1932, the Nationalist government, led byChiang Kai-shek, began preliminary work on plans in the Three Gorges. In 1939, Japanese military forcesoccupied Yichang and surveyed the area. A design, the Otani plan, was completed for the dam in anticipation of a Japanese victory over China. In 1944, the United States Bureau of Reclamation chief design engineer,John L. Savage, surveyed the area and drew up a dam proposal for the 'Yangtze River Project'. Some 54 Chinese engineers went to the U.S. for training. The original plans called for the dam to use a unique way of moving ships: ships would move into locks located at the lower and top end of the dam. Then cranes with cables with move the ships from one lock to the other. For smaller water craft, dozen would be parked in a landing craft like unit and then lifted by the crane to the next level lock. Whether this solution was considered, because the engineers then considered the height between the river above and below the dam to be to much, or as a water saving concept is unknown.  Some exploration, survey, economic study, and design work was done, but the government, in the midst of the Chinese Civil War, halted work in 1947.

After the 1949 Communist victory, Mao Zedong supported the project, but began the Gezhouba Dam project first, and economic problems including the Great Leap Forward and the Cultural Revolution slowed progress. After the 1954 Yangtze River Floods, in 1956, Mao Zedong authored "Swimming", a poem about his fascination with a dam on the Yangtze River. In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.

During the 1980s, the idea of a dam reemerged. The National People's Congress approved the dam in 1992: out of 2,633 delegates, 1,767 voted in favour, 177 voted against, 664 forfeited, and 25 members did not vote. Construction started on December 14, 1994. The dam was expected to be fully operational in 2009, but additional projects such as the underground power plant with six additional generators are expected to delay full operation until mid-2011. The ship lift is expected to be completed in 2014. The dam had raised the water level to 172.5 m (566 ft) above sea level by the end of 2008 and the maximum level of 175 m (574 ft) by October 2010.