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March 8, 2014 |
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<tr><td>Image:200407-sandouping-sanxiadaba-4.med.jpg|thumb|right|300px|Three Gorges Dam, receiving, water high-level side, 26th July of 2004</tr> <tr><td>Image:Three_gorges_dam_locks_view_from_vantage_point.jpg|thumb|right|300px|Three Gorges Dam, ship locks for river traffic to bypass the dam, May 2004</tr> </table> The Three Gorges Dam (zh-cp |c=三峡大坝 |p=Sānxi? D?b?) spans the Yangtze River at Sandouping, Yichang, Hubei province, China. Construction began in 1994. It will be the largest hydroelectricity|hydroelectric dam in the world when completed in 2009. The reservoir began filling on June 1, 2003, and will occupy the present position of the scenic Three Gorges area, between the cities of Yichang, Hubei; and Fuling, Chongqing Municipality. As with many dams under construction, there is controversy over the rights and wrongs of this project. Proponents point to the economic benefits from flood control and hydroelectric power. Opposition is mainly due to concerns about the future of the 1.9 million people who will be displaced by the rising waters; the loss of many valuable archaeological and cultural sites; as well as the effects on the environment.
Image:Threegorges.png|thumb|500px|none|Location of the Three Gorges Dam and major cities along the Yangtze River. Near the dam site overlook is a reception center containing a model of the dam. It is this model that offers the best technical overview of the project for visitors. From this display a short walk outside leads to a high overview of the entire project. Image:TGDModelSpillwayView.jpg|thumb|left|300px|Main spillway flanked by powerhouses, ship lift at right Image:TGDModelShipLocks.jpg|thumb|left|300px|Ship lift at left, double locking steps at right Image:TGDModelAuxSouthDam.jpg|thumb|left|300px|View along main dam at right. Auxiliary dam in foreground with upstream ship navigation wider in background <br style="clear:both;" /> Construction timetable 1993-1997: The Yangtze River was diverted after four years in November 1997<br> 1998-2003: The first group of generators began to generate power in 2003, and a permanent ship lock is scheduled to open for navigation the same year. <br> 2004-2009: The entire project is to be completed by 2009, when all 26 generators will be able to generate power.<br> Fund sources
Proposal of project Sun Yat-sen first proposed building a dam on the Yangtze River in 1919 for power generation purposes, but the idea was shelved due to unfavorable political and economic conditions. Major floods resurrected the idea and the government adopted it in 1954 for flood control. Vice Minister of Electric Power Li Rui initially argued that the dam should be multipurpose, that smaller dams should be built first until China could afford such a costly project, and that construction should proceed in stages to allow time to solve technical problems, according to Chinese scholars Kenneth Lieberthal and Michel Oksenberg. Later, Li Rui concluded that the dam should not be built at all since it would be too costly. He added that the dam would also flood many cities and fertile farmland, subject the middle and lower reaches of the river to catastrophic flooding during construction and would not contribute much to shipping. Sichuan province officials also objected to the construction since Sichuan, located upstream, would shoulder most of the costs while downstream Hubei province would receive most of the benefits. Lin Yishan, head of the Yangtze Valley Planning Office, which was in charge of the project, favored the dam construction, however. His optimism about resolving technical problems was further encouraged in 1958 by the favorable political climate and the support from the late chairman Mao Zedong, who wanted China to have the largest hydroelectric dam in the world, according to Lieberthal and Oksenberg. Criticisms were suppressed. But depression resulted from the disastrous Great Leap Forward and ended the preparation work in 1960. The idea resurfaced in 1963 as part of the new policies to build a "third front" of industry in southwest China. But the Cultural Revolution erupted in 1966, and in 1969 the fear that the dam would be sabotaged by the Soviet Union, now an enemy, resulted in a construction delay. In 1970, work was resumed on Gezhouba, a smaller dam downstream, but it soon ran into severe technical problems and cost overruns that seemed likely to plague the Three Gorges Dam on an even larger scale. The economic reforms introduced in 1978 underlined the need for more electric power to supply a growing industrial base, so the State Council approved the construction in 1979. A feasibility study was conducted in 1982 to 1983 to appease the increasing number of critics, who complained that the project did not adequately address technical, social, nor environmental issues. Further feasability studies were then conducted from 1985 to 1988 by Canadian International Project Managers Yangtze Joint Venture, a consortium of five Canadian engineering firms. According to Lieberthal and Oksenberg, leaders from Chongqing also demanded suddenly that the dam height be raised so substantially that it would cripple the project and free them from bearing the brunt of the costs. The new height and the demand for a more reliable study with the use of international standards resulted in a new feasibility study in 1986. But a few scientists dared to sign off on a project that had already been approved. Ecologist Hou Xueyu was among the few who refused to sign the environmental report because it falsely overstated the environmental benefits provided by the dam, failed to convey the real extent of environmental impact, and lacked adequate solutions to environmental concerns. Environmentalists at home and abroad began to protest more vociferously. Human rights advocates criticized the resettlement plan. Archeologists balked at the submergence of a huge number of historical sites. Many mourned the loss of some of the world's finest scenery. Increasing numbers of engineers doubted whether the dam would actually achieve its stated purposes. Chinese journalist/engineer Dai Qing published a book of relentless critiques of the project by Chinese scientists. Yet many foreign construction companies continued to press their governments to financially support the construction in hopes of winning contracts. Approval of project Image:three_gorges_dam_from_space.jpg|thumb|350px|Three Gorges Dam from space In the face of much domestic and international pressure, the State Council of the People's Republic of China|State Council agreed in March 1989 to suspend the construction plans for five years. After the Tiananmen Square protests of 1989, however, the government forbade public debate of the dam, accused foreign critics of ignorance or intent to undermine the regime, and imprisoned Dai Qing and other famous critics. Premier of the People's Republic of China|Premier Li Peng crusaded for the dam and pushed it through the National People's Congress in April 1992 despite the opposition or abstention from one-third of the delegates. Such actions were unprecedented from a body that usually rubberstamped all government proposals. Resettlement soon began, and physical preparations started in 1994. While the government solicited technology, services, hardware and financing from abroad, leaders reserved the engineering and construction contracts for Chinese firms. Corruption scandals have plagued the project. It was believed that contractors had won bids through bribery and then skimped on equipment and materials to siphon off construction funds. The head of the Three Gorges Economic Development Corp. allegedly sold jobs in his company, took out project-related loans and disappeared with the money in May 2000. Officials from the Three Gorges Resettlement Bureau were caught embezzlement|embezzling funds from resettlement programs in January 2000. Much of the project's infrastructure was so shoddy that Premier Zhu Rongji ordered it ripped out in 1999 after a number of high-profile accidents. To offset construction costs, project officials had quietly changed the operating plan approved by the NPC to fill the reservoir after six years rather than 10. In response, 53 engineers and academics petitioned President Jiang Zemin twice in the first half of 2000 to delay full filling of the reservoir and relocating the local population until scientists could determine whether a higher reservoir was viable given the sedimentation problems. Construction continued regardless. Cost The project is thought to have cost more than any other single construction project in history, with unofficial estimates as high as US$75 billion or more. Officials report, however, that the plan is within its US$25 billion budget and insisted early on that the project would pay for itself through electricity generation. Environment Hydro-electric power is a renewable energy source that does not generate waste, although there is new evidence suggesting that dams generate carbon dioxide and substantial amounts of methane<sup>#References|1</sup> due to micro biotic activity in their reservoirs. Dams by their nature alter the ecosystem and threaten the habitats of various endangered species of fish, waterfowl and other animals. The Chinese River Dolphin, for example, is on the edge of extinction and will lose habitat to the dam. Logging in the area was required for construction and adds to erosion. Local culture and natural beauty The 600 km (370 mile) long reservoir will inundate some 1,300 archeological sites, and change the legendary beauty of the Three Gorges. Many cultural and historical relics are being moved to higher ground. Navigation The installation of ship locks are intended to increase river shipping from 10 million to 50 million tons annually, with transportation costs cut by 30 to 37 percent. Shipping will become safer, since the gorges have historically been notoriously dangerous to navigate. Critics argue, however, that heavy siltation will clog ports such as Chongqing within a few years based on the evidence from other dam projects. Flood control The reservoir's 22 km³ (28.9 billion cubic yard) flood storage capacity will lessen the frequency of big downstream floods from once every 10 years to once every 100 years. But critics believe that the Yangtze will add 530 million tons of silt into the reservoir on average per year and it will soon be useless in preventing floods. Increased sedimentation resulting from the dam could increase the already high flood level at Chongqing. Probe International asserts that the dam does not address the real source of flooding, which is the loss of forest cover in the Yangtze watershed and the loss of 13,000 km² of lakes (which had greatly helped to alleviate floods) due to siltation, reclamation and uncontrolled development. In an annual report http://www.defenselink.mil/pubs/d20040528PRC.pdf to the United States Congress, the United States Department of the Defense|Department of Defense cited that Republic of China|Taiwanese "proponents of strikes against the mainland apparently hope that merely presenting credible threats to China's urban population or high-value targets, such as the Three Gorges Dam, will deter Chinese military coercion." The notion that the Military of Taiwan|ROC military would seek to destroy the Dam provoked an angry response from the mainland state media. People's Liberation Army|PLA General Liu Yuan was quoted http://news.bbc.co.uk/1/hi/world/asia-pacific/3654772.stm in the China Youth Daily saying that the PRC would be "seriously on guard against threats from Taiwan independence terrorists". Despite a claim by ROC Deputy Defence Minister Tsai Ming Hsian on the contrary, most analysts believe the Taiwanese neither have the ability nor will seek such technology to bomb the Three Gorges Dam due to the threat by Beijing to respond with overwhelming force. In September 2004 the China Times reported that heavily armed guards had been deployed to the area to fend off a possible terrorist attack, but made no mention of who might want to target the Dam. There are two hazards uniquely identified with the dam <sup>#References|2</sup>; sedimentation modeling is unverified, and the dam sits on a seismic fault. Excessive sedimentation can block the sluice gates, which can cause dam failure under some conditions. This was a contributing cause of the Banqiao Dam failure in 1975 that precipitated the failure of 61 other dams and resulted in over 200,000 deaths. Also, the weight of the dam and reservoir can theoretically cause Induced seismicity|induced seismicity, as happened with the Katse Dam in Lesotho. Distribution of the power generated at the Three Gorges Dam will not be limited to the surrounding Central China Power Network (covering the provinces of Henan, Hubei, Hunan, and Jiangxi). Instead, power is also to be transmitted westwards into the Chongqing and the Sichuan Power Grids as well as all the way to the east and south-east coast. Whereas power will be delivered into the Chongqing and Sichuan grids via 500 Volt|kV Alternating current|AC transmission lines, HVDC-technology will be used for eastwards delivery. Two high-capacity powerlines, the HVDC Three Gorges-Changzhou and the HVDC Three Gorges-Guangdong, will transmit power eastwards (to the Shanghai area) and southwards (to Guangdong Province).
#http://www.newscientist.com/article.ns?id=dn7046 New Scientist report on greenhouse gas production by hydroelectric dams. #Topping, Audrey Ronning. Environmental controversy over the Three Gorges Dam. Earth Times News Service. #http://www.abb.com/global/abbzh/abbzh251.nsf!OpenDatabase&db=/global/gad/gad02181.nsf&v=17EA&e=us&m=100A&c=C1256D71001E0037C1256834003AF40D article by ABB on use of HVDC-technology for distribution of power generated at the Three Gorges Dam
<!-- Interlanguage links --> de:Drei-Schluchten-Damm eo:Tri Gorgxoj Barajxo es:Presa de las Tres Gargantas fr:Barrage des Trois Gorges nl:Drieklovendam ja:三峡ダム fi:Kolmen solan pato zh-cn:三峡水电站 Category:Buildings of China Category:Dams This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Three Gorges Dam".
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