Civil Engineering

Three Gorges Dam

World's Largest Water Conservation Project

China's Three Gorges Project is the largest water conservation project in the world. Taking the total amount of concrete work as one example, the Three Gorges Project totals 26.43 million cubic meters, 2.5 times the figure for the Gezhouba Barrage project and twice that of the Itaipu project in Brazil, which is currently the largest water conservation projects in the world. The main construction targets of the Three Gorges Project are:

China now boasts a contingent of approximately 250,000 workers employed in constructing the water conservation and hydropower projects. Their experience in building concrete gravity dams, hydropower plants, and large ship locks have prepared them to build the Three Gorges Project.

World's Largest Hydropower Plant

Upon completion, the Three Gorges Project will be the world's biggest hydropower plant in terms of both total installed capacity and annual average power generation volume.

Twenty-six turbine generator sets, with a per-unit generation capacity of 700,000 kilowatts, will be installed on the left and right banks of the Three Gorges Hydropower Station. The overall generation capacity is estimated at 18.2 million kilowatts. The annual power generation is estimated to average 84.68 billion kilowatt hours (KWH), equivalent to one-seventh of China's total in 1992.

The Three Gorges Hydropower Station will be hooked up with thermal power and hydroelectric grids in central and eastern China, thus improving the economy and reliability of the electric grids.

Moreover, China has mapped out state energy strategies by transporting coal resources in northern China to the southern regions and transmitting electricity generated from the western parts to eastern localities in a bid to ease the energy shortage in central and eastern China.

Three Gorges Project to Take 17 Years

The ongoing Three Gorges Project, which will be the world's largest water conservation facility when completed, will take 17 years to build. Construction of the project consists of three stages.

  1. The preparatory and first-phase projects spans five years from 1993-1997, whose completion is signaled by the damming of the Yangtze River on November 8.
  2. The second phase will run from 1998 to 2003. This phase will be completed when the first generating unit in the left-bank power plant goes on line and the permanent ship lock begins operation.
  3. The third phase is planned for 2004-2009. This final phase includes the completion of all 26 electricity-producing turbogenerators.

On October 14, 1997, the 63rd Executive meeting of the State Council set November 8 as the date to block the Yangtze River. That will mark the end of the first phase construction and the beginning of the second phase.

Dam Won't Affect Navigation on Yangtze River

The Yangtze River, the world's third longest, is one of China's leading transportation routes. One guarantee made by developers of the Three Gorges Project ensures smooth navigation at the construction site during the six-year second phase (1997-2003).

A water diversion channel opened formerly on October 6. During the next-phase construction through 2003, ships will use the channel to bypass the dam site or use temporary locks now being built on the north bank of the Yangtze.

Engineers said that ships can safely pass through the channel except for peak water flow seasons. When the water flows faster than 25,000 cubic meters per second, it could be difficult for large ships to use the channel. The maximum flow for smaller ships is between 10,000 and 15,000 cubic meters per second.

Temporary ship locks are being built to ensure safe passage during the flood season which normally begins in May. The diversion channel will guarantee that passenger and cargo transport needs are met in the upper reaches of the Yangtze river during construction. Permanent ship locks will be in operation after the year 2003.

Three Gorges Reservoir Inundation

The Three Gorges Reservoir will inundate 632 sq. km., the world's largest inundated area by a single project. The normal water level of 175 meters will be achieved in the year 2003, with the reservoir covering 1,045 and stretching some 663 km, an area capable of controlling floods expected to occur twice in one decade.

The resettlement effort and the area to be inundated are unprecedented in Chinese history, with inundation affecting 365 townships in 21 counties, cities or districts in Sichuan and Hubei provinces. Some 844,000 people are scheduled for resettlement, with unforeseen factors most likely raising the figure to 1.2 million people.

The Three Gorges Reservoir will inundated 31,000 hectares of farmland, and will require the relocation of 1,599 industrial and mining enterprises, as well as power transmission and telecommunications facilities, harbors, small and medium-sized hydro-electric power plants, roads and pumping stations.

The new reservoir, typical of facilities in gorges, will not have a so-called "big-belly" section similar to other facilities built on lakes.