Three Gorges Dam
Location: China

View of the locks of the Three Gorges Dam, Yangtze River, China
by Richard Chambers, http://commons.wikimedia.org/wiki/Image:Three_gorges_dam_locks_view_from_vantage_point.jpg, used under GNU Free Documentation License


The Three Gorges Dam is the largest hydroelectric river dam in the world, as well as the biggest construction project on earth. It is built across the Yangtze River in Sandouping, Yichang, Hubei Province, China. This mammoth dam is 2335m (7660ft) long and 185m (616ft) high. Its base is 115m wide while its top is 40m wide. The project consumed 28 million cubic metres of concrete and 463 thousand tons of steel. The Three Gorges Dam creates a 600km long man-made reservoir behind it. This reservoir can hold 39 cubic kilometres of water, allowing the dam to generate 22 500MW of electrictiy, thus cementing its claim as the largest hydroelectric power station in the world.

The idea to dam the Yangtze River was started as early as 1919 when Dr Sun Yat Sen presented his paper, The International Development of China. However, at that time, the technology to build so big was not yet realised. The "trial run" was the construction of the Gezhouba Dam, also across the Yangtze, between 1970 and 1988. The Three Gorges project only got started in 1993, with the approval of the National People's Congress. Actual construction began in 1994 and the structure was completed on 20 May, 2006, nine months ahead of schedule. Although the reservoir began to fill since 1 June 2003, the dam will only be fully operational by 2009.

The construction of the Three Gorges Dam came at a tremendous cost. It displaced 1.13 million people who were affected by the rising water. Many valuable archaeological and cultural sites were also inundated. The scenic sights of the Three Gorges were similarly made less dramatic with the rise in the water level. The entire project would cost no more than 180 billion yuan (US$22.5 billion), less by 20 billion yuan than the original projection. It will take about 10 years to recover the cost.

The benefit of the Three Gorges Dam is the reduction in dependency on coal consumption by 31 million tons per year, and this cuts emission of 100 million tons of greenhouse gas, as well as millions of tons of dust, sulfur dioxide, and 370,000 tons of nitric oxide, 10,000 tons of carbon monoxide and large amounts of mercury into the atmosphere. As of 14 May, 2007, the 14 generators on the north side of the dam have started full operations since 18 October 2006 when the water level reached 156m. The Three Gorges Dam was expected to meet 10% of China's electricity consumption needs. However, China's demand for electricity has outpaced projections, so that the dam will only support 3% of the total electricity consumption of the country.