1. A Dream for Generations to Come True
The idea of building a gigantic dam in the Three Gorges area to harness the
Historically, the population in the middle and lower reaches of the
Currently, 15 million people and 1.6 million hectares of land along the Jingjiang section of the
With its total installed capacity of 18,200 MW, the Three Gorges Hydropower Station will generate 84.7 billion KWH a year, one-ninth of the national total generated power.
Thirdly, the project will enable 10,000-ton towboats to sail up-stream as far as
2. Problems to Be Resolved
The project also presents daunting problems which should be properly handled and solved to avoid any possible undesired impacts. These include resettlement of population, environmental protection, fund raising, etc.
About 1 million people will be relocated owing to the construction of the project. The government has attached great importance to the issue and decided to appropriate large sums of money for the resettlement program. The guiding principle of the program is that the life of the relocatees can only be improved. For this purpose, the government has adopted development-oriented resettlement, in other words, to combine resettlement with local economic development. The relocatees find higher-paying jobs in the newly set up businesses, which are usually located within the same country or city. Therefore, they feel quite at home and enjoy a better living in their new homes.
There has been concern about possible negative impacts on the environment by the project both at home and abroad.
This issue has been given very serious consideration and numerous measures have been taken to ensure environmental protection. For instance, the project construction will affect the habitats of Chinese river dolphin and Chinese sturgeon. So, the present protection areas and artificial breeding fields for them will be further perfected. It is not insignificant that the project will supply clean energy, replacing the burning of 50 million tons of raw coal annually. According to calculations, the discharge into the atmosphere of 100 million tons of carbon dioxide, 1.2-2 million tons of sulphur-dioxide, 10,000 tons of carbon monoxide, along with large amount of flying dust will be drastically reduced. 44 historical relics will be affected by the project construction and measures will be taken for their protection. For example, the White Crane Backbone, an ancient identification record of dry seasons in the history will be relocated. The Sibaozhai in
By the year 2009 when the project is completed, the total investment for the project will amount to US $28 billion. The funds for the project come from four sources: the Three Gorges Construction Funds, power revenues from the existing Gezhouba Hydropower Plant, power revenues from the Three Gorges Project starting from the year 2003 and loans and credits from the State Development Bank. In spite of the above sources, it is estimated that there exists a fund gap of $7.1 billion. This gap will be made up through domestic loans, export credits, overseas commercial loans and bond issuing, etc. As the project construction lasts 17 years and funding comes from multiple sources, fund raising does not present a difficult problem. The funding of the project has been smooth and no shortage of money has so far affected the progress of the project.
3. Progress in the Project
After the resolution on the Three Gorges Project was adopted in 1992, the State Council immediately started preparations for the project. On
The Chinese government and people are confident that, relying mainly on their own efforts and also through international cooperation, they will successfully build up the Three Gorges Project.
Three Gorges Dam: worth the costs?
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In 1919, Dr. Sun Yat-sen, the political revolutionary known as the “Father of Modern China,” envisioned a massive hydroelectric dam spanning the
Stretching 1.5 miles wide, 600 feet high and 400 miles long, the dam already occupies such a large expanse of land that it is more visible from space than any river. The Chinese government claims that the dam will solve so many economic issues that the benefits will outweigh any problems it might cause.
Ocean freighters will be able to access the country’s interior for six months out of the year, which will stimulate the agricultural and manufacturing industries located there. The electricity generated by the dam will be equivalent to 18 nuclear power plants. And, hopefully, the dam’s presence will help curb the
Anything that ends repeated flooding and offers an alternative to coal-burning power seems like a promising endeavor. However, the cons of the Three Gorges Dam raise questions as to how, in an age of increasing social and environmental awareness, its construction has been allowed to continue without serious modifications.
Journalist Steven Mufson of the Washington Post calls the Three Gorges Dam “a vision that combines ambition worthy of pyramid-building Pharaohs with the destructiveness of open-pit coal mining.” Like mining and other economically lucrative projects with devastating results, the Three Gorges Dam could be a kind of twenty-first century Titanic: an overzealous declaration of technological progress.
The most publicized concerns regarding the dam are environmental. In addition to the possibility of pollutants building up behind the dam and contaminating the region’s water supply, wildlife is also threatened by the construction of the dam. The entire area had to be logged before construction could begin, destroying valuable habitats. Construction of the dam has already contributed to the near extinction of several species, including the Baiji, or
According to CNN.com, journalist Dai Qing, who was thrown in jail for ten months after criticizing construction of the dam in 1989, calls the project “the most environmentally and socially destructive project in the world.” She proposes using tributaries of the Yangtze to create smaller, less damaging projects that might accomplish some of the same energy goals as the Three Gorges Dam.
But perhaps even worse than the potential environmental damage is the potential human cost of the project. As many as 1.4 million Chinese residents have already been displaced as a result of the project, with four million more expected to be relocated in the next 10 to 15 years. The dam will also completely submerge 1,300 valuable historical and archeological sites such as the burial grounds of the ancient Ba people.
Worst of all, despite the regular floods the dam could prevent, if the dam itself were to break, the entire Yangtze delta would become flooded, possibly taking millions of lives. Those lives would also be at risk, critics have mentioned, if
These are only hypothetical consequences. Real consequences, however, are already evident in the areas surrounding the dam. In the hurry to put such massive technology into action, it is clear that shortcuts in both construction and design have been taken. Geologists have found water seeping out of the reservoir into the ground, the banks of the reservoir have been weakened by enormous pressure changes and fatal landslides have increased dramatically in the region.
Whether the most significant problems that arise out of the construction of the Three Gorges Dam are human, environmental or both, the dam represents the kind of overextended display of human innovation that usually results in unforeseen consequences—only this time those consequences are well within our sights, and they are downright frightening.
Corruption, sloppy construction, lack of foresight into environmental consequences and disregard for human life have all contributed to the construction of this dam. Of course we need alternative energy, but the purpose of the Three Gorges Dam is not to reduce CO2 emissions, it’s to power
Three Gorges Dam
From Wikipedia, the free encyclopedia
| Three Gorges Dam | |
|
| |
| Official name | 长江三峡大坝 |
| Impounds | |
| Creates | |
| Locale | Sandouping, Yichang, Hubei, |
| Maintained by | |
| Length | 2,335 metres (7,661 ft) |
| Height | 101 metres (331 ft) |
| Width (at base) | 115 metres (377 ft) |
| Construction began | |
| Construction Cost | Estimated 180 billion yuan (39 billion U.S. dollars) |
| Reservoir information | |
| Capacity | 39.3 km3 (9.4 cu mi) |
| Catchment area | 1,000,000 km2 (386,102 sq mi) |
| Surface area | 1,045 km2 (403 sq mi) |
| Bridge information | |
| Carries | 177 |
| Toll | £10.00 |
| 7649 | |
| Geographical Data | |
|
| |
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 river dam that spans the Yangtze River (Chinese: 扬/洋子; pinyin: Yángzǐ) in Sandouping, Yichang, Hubei, China. It is the largest hydroelectric power station in the world. Except for a planned ship lift, all the original plan of the project was completed on
As with many dams, there is a debate over costs and benefits. Although there are economic benefits such as flood control, clean hydroelectricity and navigation, there are also concerns about the relocation of people, siltation, loss of archaeological and cultural sites and the impact on regional ecosystem.[3]
Project history
In his poem "Swimming" (1956), engraved on the 1954 Flood Memorial in Wuhan, Mao Zedong envisions "walls of stone" to be erected upstream.[4]
The dam was originally envisioned by Sun Yat-sen in The International Development of China in 1919.[5] In 1932 the Nationalist government, led by Chiang Kai-shek, began preliminary work on plans for a dam in the Three Gorges. Then in 1939 the Japanese military forces occupied Yichang and surveyed the area. A design, the Otani plan, was completed for the dam in anticipation of a Japanese victory over
After the 1949 communist victory, the leader Mao Zedong supported the project, but the Gezhouba Dam project was begun first and economic problems including the Great Leap Forward and the Cultural Revolution slowed progress. In 1958, after the Hundred Flowers Campaign, some engineers who spoke out against the project were imprisoned.[8]
During the 1980s plans were revived. Pushed through by Li Peng, the dam was approved by the National People's Congress in 1992 with a record number of abstentions and dissenting votes.[citation needed] The construction started on December 14, 1994.[9] The dam was expected to be fully operational in 2009, but due to additional projects such as the underground power plant with 6 additional generators, and due to the complexity of the ship lift, the dam is not expected to become fully operational until about 2011.[8] The dam will raise the water level the third time to its designed maximum water level (175 m above sea level) by the end of 2008.[10]
Map of the location of the Three Gorges Dam, Sandouping,
The dam wall is made of concrete and is about 2,309 metres (7,575 ft) long, and 101 metres (331 ft) high. The wall is 115 metres (377.3 ft) thick on the bottom and 40 metres (131.2 ft) thick on top. The project used 27,200,000 cubic metres (35,600,000 cu yd) of concrete, 463,000 tonnes of steel, enough to build 63 Eiffel Towers, and moved about 102,600,000 cubic metres (1.342E+8 cu yd) of earth.[11]
When the water level is maximum at 175 metres (574 ft) over sea level (91 metres (299 ft) above river level), the reservoir created by the Three Gorges Dam is about 660 kilometres (410 mi) in length and 1.12 kilometres (0.70 mi) in width on average, and contains 39.3 km3 (9.4 cu mi) of water.The total surface area of the reservoir is 1045 km². The reservoir will flood a total area of 632 km² of land compared to the 1,350 km² of reservoir created by the Itaipu Dam.[12]
Three Gorges Dam Francis Turbine
When finished, the project will have cost 180 billion yuan, over 20 billion yuan less than the initial estimated budget of 203.9 billion yuan, just under 30 billion USD. This is because the calculation accounts for the effect of inflation, and the lower costs are attributed to a low inflation rate in recent years.[13] Until the end of 2008, the total investment reached 148.365 billion yuan, among which, 64.613 billion yuan on construction, 68.557 billion yuan on the relocation of affected residents and 15.195 billion yuan was spent on the interests of financing.[14] It is estimated that the cost of construction will be recovered when the dam has generated 1000 TWh of electricity, which is estimated to sell for 250 billion yuan. Cost recovery is expected to occur ten years after the dam starts full operation.[5]
Sources for funding include the Three Gorges Dam Construction Fund, profits from the Gezhouba Dam, policy loans from the China Development Bank, loans from domestic and foreign commercial banks, corporate bonds, and revenue from Three Gorges Dam before and after it is fully operational, with additional charges for electricity contributing to the Three Gorges Construction Fund. The additional charges are as follows: Every province receiving power from the Three Gorges Dam has to pay an additional charge of ¥7.00 per MWh. Provinces that will not receive power from the Three Gorges Dam have to pay an additional charge of ¥4.00 per MWh. Tibet does not have to pay any additional money.[15]
Hydroelectricity generation and distribution
Electricity production in
The Three Gorges Dam is the world’s largest hydro-electric power station by total capacity, which will be 22,500 MW.[5] It will have 34 generators. 32 will be main generators, each with a capacity of 700 MW, and the other 2 will be plant power generators, each with capacity of 50 MW. Among those 32 main generators, 14 of them are installed in the north side of the dam, 12 in the south side and the remaining 6 in the underground powerplant in the mountain south of the dam. After completion, the expected annual electricity generation will be over 100 TWh,[16] 18% more than the originally predicted 84.7 TWh, since 6 generators were added in 2002.
Each of the main generators weighs about 6000 tonnes and are designed to produce at least 700 MW of power. The designed head of the generator is 80.6 m. The flow rate varies between 600 m3/s to 950 m3/s depending on the head available. The Three Gorges Dam project installs Francis turbines. The diameter of the turbine is 9.7/10.4 m (VGS design/Alstom's design). It rotates at a speed of 75 rpm. The normal rated power of the generator is 778 MVA. The maximum power is 840 MVA. The power factor is 0.9. The generator produces electrical power at 20 kV. The outer diameter of the generator stator is 21.4/20.9 m. The inner diameter is 18.5/18.8 m. The height of the stator is 3.1/3 m. It is the biggest stator in the world. The load at the bearing is 5050/5500 tonnes. The average efficiency of the generators is over 94%, and the highest is 96.5%.[17]
The generators are manufactured by two joint ventures. One of them includes Alstom, ABB, Kvaerner and the Chinese company Haerbin Motor. The other includes Voith, General Electric, Siemens (abbreviated as VGS), and the Chinese company Oriental Motor. The technology transfer agreement was signed together with the contract. More than 8 of the 32 generators are made in
Generator installation progress
The 14 generators in the north side of the dam have already been installed. The first one (No.2 ) started to power on
The 12 generators in the south side of the dam have already been installed.The first generator (No. 22) in the south side of the dam started working on
The ninth generator in the south side (No. 19) started working on
Added to the project in 2002, the underground power plant and its six generators are still under construction.[24][25]
As of
Three Gorges Dam (left), Gezhouba Dam (right).
| Annual Production of Energy | ||
| Year | Number of
| TWh |
| 2003 | 6 | 8.607 |
| 2004 | 11 | 39.155 |
| 2005 | 14 | 49.090 |
| 2006 | 14 | 49.250 |
| 2007 | 21 | 61.600 |
| 2008 | 26 | 80.812[28] |
| Total | 26(32) | 288.514 |
The electricity generated by the Three Gorges Dam project was sold to the State Grid Corporation and China Southern Power Grid at a flat rate of ¥250 per MWh ($35.7 US) until
The power distribution and transmission of the Three Gorges Dam project cost about 34.387 billion Yuan. It was completed in December 2007, one year ahead of time.[31]
Power is sent in three directions. The 500 kV DC transmission line to the East China Grid has a capacity of 7,200 MW. There are three 500 kV DC transmission lines: HVDC Three Gorges-Shanghai (3,000 MW), HVDC Three Gorges-Changzhou (3,000 MW) and HVDC Gezhouba - Shanghai (1,200 MW). The 500 kV AC transmission line to Central China Grid has a capacity of 12,000 MW. The other 500 kV DC transmission line HVDC Three Gorges-Guangdong to South China Grid has a capacity of 3,000 MW and supplies Guangdong.[32]
In the original plan, it was expected to provide 10% of electricity consumption in
Environmental contribution of the dam
Direct reduction of air pollutant and greenhouse gas emission
According to The National Development and Reform Commission of China, it takes 366 grams of coal to generate 1 kWh of electricity in
Since the dam started generating power on
Reduction of greenhouse gas due to navigation
From 2004 to 2007 a total of 198 million tonnes of goods passed through the Three Gorges Dam ship locks. The freight capacity of the river increased 6 times and the cost of shipping reduced by 25%, compared to previous years, which reduces carbon dioxide emission by 630,000 tonnes. Comparing to highway transportation, the amount of fuel that Three Gorges Dam project saved between the year of 2004 and 2007 is equivalent to 4,100,000 tonnes of standard coal. Thus it reduces carbon dioxide emission by 10 million tonnes.[37]
Since the construction of the Three Gorges Dam, many waste water treatment plants have been completed to reduce the water pollution from the large populated city
The Three Gorges Dam pushes the Chinese government to think seriously about the environmental issues associated with the dam, such as deforestation and water pollution.[citation needed] “The FAO’s research suggests that the Asia-Pacific region will, overall, gain about 6,000 square km of forest in 2008. That is quite a turnaround from the 13,000 square km net loss of forest each year in the 1990s. The main reason is
Flood control and drought relief
The most significant function of the dam is to control flooding, which is a major problem of a seasonal river like the Yangtze. Millions of people live downstream of the dam, and many large and important cities like Wuhan, Nanjing and
The reservoir's flood storage capacity is 22 km3(18 million acre feet). This capacity will reduce the frequency of major downstream flooding from once every 10 years to once every 100 years. With the dam, it is expected that major floods can be controlled. If a "super" flood comes, the dam is expected to minimize its effect.[5]
In 1954 the river flooded 193,000 km2 (74,518 sq mi) of land, killing 33,169 people and forcing 18,884,000 people to move. The flood covered Wuhan, a city with 8 million people, for over three months, and the Jingguang Railway was out of service for more than 100 days.[5] In the event of a recurrence of the 1954 flood that carried 50 billion m3 of water, the Three Gorges Dam could only divert the water above Chenglingji, still leaving 30 to 40 billion m3 of flood water to be diverted.[41] Also the dam will not protect the large tributaries such as the Xiangjiang, Zishui, Yuanshui, Lishui, Hanjiang, and Ganjiang from flooding, due to the location of the dam.
In 1998 a flood in the same area caused billions of dollars in damage. The Chinese government asked for support from its military to fight the flooding. 2039 square kilometers of farm land was flooded. The flood affected more than 2.3 million people, and 1,526 were killed.[42]
The Dam discharges its reservoir during the dry season between December and March every year.[43] This increases the flow rate of the river downstream, and provides more fresh water for agricultural and industrial usage. It also improves the navigation conditions during dry season. The water level upstream drops from 175 m to 145 m,[44] leaving room for the flooding season. This also increases the power output of the Gezhouba Dam downstream.
Ship locks for river traffic to bypass the Three Gorges Dam, May 2004
The installation of ship locks is intended to increase river shipping from 10 million to 100 million tonnes annually, with transportation costs cut by 30 to 37%. Shipping will become safer, since the gorges are notoriously dangerous to navigate.[37] Each of the two ship locks is made up of 5 stages taking around 4 hours in total to complete and have a capacity of 10,000 tons.[45] Critics argue, however, that heavy siltation will clog ports such as Chongqing within a few years based on the evidence from other dam projects.
The locks are designed to be 280 m long, 35 m wide, and 5 m deep (918 x 114 x 16.4 ft).[46][47] That is 30 m longer than those on the St Lawrence Seaway, but half as deep. Before the dam was constructed, the maximum freight capacity of the river at the Three Gorges site was 18.0 million tonnes per year. From year 2004 to 2007, there were total of 198 million tonnes of freight passed through the Three Gorges Dam ship locks. The freight capacity of the river increased 6 times and the cost of shipping reduced by 25%, comparing to the previous years. The total capacity of the ship locks is expected to reach 100 million tonnes.[37]
In addition to the canal locks, the Three Gorges Dam will be equipped with a ship lift, a kind of elevator for vessels.[48] The ship lift is designed to be capable of lifting ships of up to 3,000 tons.[49][50][51] In the original plan its capacity was to be 10,000 tons. The ship lift was not yet complete when the rest of the project was officially opened on
During the planning stages in the 1990s it was estimated that 1.13 million residents would be forced to relocate; the final number (as of June 2008) ended up with 1.24 million after the last town called Gaoyang in Hubei
There have been accusations of corruption over money sent to the town of
Main article: Environmental issues with the Three Gorges Dam
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| It has been suggested that Environmental issues with the Three Gorges Dam be merged into this article or section. (Discuss) |
Of the 3,000 to 4,000 remaining critically endangered Siberian Crane, a large number currently spend the winter in wetlands that will be destroyed by the Three Gorges Dam. The dam also contributed to the functional extinction of the Baiji, the
While logging in the area was required for construction[citations needed]which adds to erosion, stopping the periodic and uncontrolled flooding of the river will lessen bank erosion in the long run. The build up of silt in the reservoir will, however, reduce the amount of silt transported by the Yangtze River to the Yangtze Delta and could reduce the effectiveness of the dam for electricity generation and, perhaps more importantly, the lack of silt deposited in the peninsula could result in erosion and sinking of coastal areas.
Effect on local culture and aesthetic values
The 600 kilometer (375 mi) long reservoir has flooded or will flood some 1,300 archaeological sites and will alter the appearance of the Three Gorges as the water level rises over one hundred meters at various locations.[64] Cultural and historical relics are being moved to higher ground as they are discovered but the flooding of the Gorge will undoubtedly cover some undiscovered relics. Some other sites cannot be moved because of their location, size or design. For example the hanging coffins site high in the Shen Nong Gorge is inherently part of the sheer cliffs themselves.[65]
There are two hazards uniquely identified with the dam.[66] One is that sedimentation projections are not agreed upon, and the other is that the dam sits on a seismic fault.
The Three Gorges area currently has 10% forestation, down from 20% in the 1950s. At current levels 80% of the land in the area is experiencing erosion causing about 40 million tons of sediment to slide into the Yangtze annually.[63] The relocation of people from the reservoir area will cause further deforestation and erosion due to agricultural needs.
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 20,000 deaths. Critics believe that the Yangtze will add 530 million tons of silt into the reservoir on average per year; in time, this silt could accumulate behind the walls of the dam, clogging the turbines' entranceway. However, because
Some hydrologists think that this could make downstream riverbanks more vulnerable to flooding.[citation needed]
The city of
The Benthic sediment build up is a cause of biological damage and reduction in aquatic biodiversity.[68]
In an annual report to the United States Congress, the Department of Defense cited that in Taiwan, “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.”[69]
The notion that the Military of the Republic of China would seek to destroy the Dam provoked an angry response from the mainland China media. People’s Liberation Army General Liu Yuan was quoted in the China Youth Daily saying that the People’s Republic of China would be "seriously on guard against threats from Taiwan independence terrorists".[70]
In order to maximize the utility of the Three Gorges Dam and cut down on sedimentation from the Jinsha, a tributary of the Yangtze river, China plans to build a series of dams upstream of the Yangtze river, including Wudongde Dam, Baihetan Dam, Xiluodu Dam, Xiangjiaba Dam, and downstream of Jinsha. The total capacity of those four dams is 38,500 MW,[71] almost double the capacity of the Three Gorges.[72] There are also another eight dams in the midstream of the Jinsha and eight more upstream of it.[73]
In Max Brooks’ novel World War Z, the large artificial lake upstream of the dam is the site of the initial zombie outbreak before the war; a superstitious character suggests that the outbreak is a retribution for the destruction of ancient holy sites. Later in the novel, the Dam is overrun by zombie hordes, which make the emergency pressure release valves impossible to reach. This eventually results in the Three Gorges Dam rupturing, resulting in a massive tsunami which races to the ocean, destroying what remains of
In the novel Dragon Bones by Lisa See, a murder investigation takes place at the Three Gorges Dam.[75]
In the video game Civilization IV the dam is a World Wonder, providing power to the entire continent.[5]
In the video game Command & Conquer: Generals, the dam is blown up by both the Chinese government and a terrorist organization under plot lines. (It is first blown up by the Chinese as a desperate effort to drown the terrorists with the water behind the dam, while the terrorists blow up a rebuilt dam to flood the Chinese.) The series is banned in
Jia Zhangke’s film, Still Life, describes the destiny of two couples with connections to the dam.[5]
Yung Chang's 2007 award-winning documentary film, Up the Yangtze features the effects of the dam on various people along the
Artists David Kelley and Patty Chang's video installation, "Flotsam Jetsam", features actors from a local Chinese Opera troupe performing on board an American Nuclear Submarine that is passing through the Three Gorges Dam to the reservoir up river. The sub's journey becomes an imaginative performance exploring identity, space and memory.
"Kilowatt Dynasty," 2000, is a video by London-based Dutch artist Saskia Olde Wolbers. The fictional work is narrated by an Anglo-Chinese girl whose parents meet in an underwater shopping center constructed entirely of glass. The mother is the hostesses of a teleshopping program that shoots on location; the father is a radical environmentalist who kidnaps her.
Biggest Flood Control Benefit in the World 
Although the TGP Reservoir is not the reservoir with the biggest capacity in the world, its reserved flood control capacity can help cut flood peak by 27,000 ～ 33,000 m3/s, the biggest for a water conservancy project in the world.
When the TGP is completed, the flood control standard of the middle and lower reaches of the Yangtze, especially the Jingjiang Section, will be largely upgraded from the present level of preventing under-10-year floods to that of preventing 100-year floods. So 15 million people and 1.5 million hectares of farmland in the Jianghan Plain are relieved from flood threats, and devastating plagues of massive death caused by big floods are avoided.
Floods records of
| 1931.... | The flood in 1931 struck an area of 130,000 km2 with 3.39 million ha farmland and 1.8 million houses inundated, 28.55 million people affected, and 145,000 people killed, causing approximately an economic loss of 1.345 billion YinYuan. |
| 1935.... | The flood in 1935 hit an area of 89,000 km2 in the middle and lower reaches of the Yangtze River, with six provinces, Hubei, Hunan, Jiangxi, Anhui, Jiangsu, Zhejiang and 10 million people affected, 1.51 million ha of farmland inundated, 142,000 people killed, causing approximately an economic loss of 0.355 billion YinYuan. |
| 1949.... | The flood in 1949 inundated 1.81 million ha farmland, affected 8.1 million people and cost the lives of 5699 people in the middle and lower reaches of the |
| 1954.... | The damages caused by the flood in 1954 in the middle and lower reaches: totally 3.18 million ha farmland and 4.27 million houses inundated, 18.884 million people and 123 counties and cities affected, 33169 people killed and the interruption of the Beijing-Guangzhou Railway for 100 days. |
| 1998.... | The flood in 1998 struck a large area of the |
Remarkable Power Generation Benefit
The Three Gorges Hydropower Plant (TGHP) contains twenty-six turbine-generator units, each with installed capacity of 700MW, not including the six more 700MW units in the Right Bank Underground Powerhouse under construction. Its total installed capacity amounts to 18200MW, and its expected annual average power generation accounts up to 84.7 TWH, so the TGHP ranks the biggest one in the world with remarkable power generation benefit. At present, TGHP electricity is sent unceasingly to
Major Parameters of the TGHP units and abroad power plants
| Parameters | Three Gorges Project
| Grand Coulee
| Itaipu
| Guri
| |
| Turbine | | | | | |
| Maximum Head(m) | 113.0 | 108.2 | 126.7 | 146 | 100.5 |
| Rated Head(m) | 80.6 | 86.9 | 112.9 | 130 | 93 |
| Minimum Head(m) | 71.0(61.0) | 67.0 | 82.9 | 111 | 76 |
| Rated Output (MW) | 710 | 612/716 | 715 | 610 | 508 |
| Maximum Output(MW) | 852 | 827 | 740/808 | 730 | 508(505) |
| Rated Spinning Speed(r/min) | 75 | 85.7 | 90.9/92.3 | 112.5 | 93.8 |
| Runner Diameter(m) | 9.525(9.800) | 9.86/9.22 | 8.45 | 7.163 | 7.5 |
| Generator | | | | | |
| Rated Capacity(MW) | 778 | 718 | 823.6/737.0 | 700 | 500 |
| Maximum Capacity(MW) | 840 | 710/825.6 | 823.6/766 | 805 | |
| Frequency(Hz) | 50 | 60 | 50/60 | 60 | 50 |
| Cooling | Water Cooling of Statar | Water Cooling of Statar | Water Cooling of Statar | Air Cooling | Water Cooling of Statar |
| Rated Voltage(KV) | 20 | 15 | 18±5% | 18 | 15.75 |
| Insulation Levels | F | B | F | B | |
| Thrust Load(t) | 4,050(4,100) | 4,700 | 4,056&4,400 | 2,667 | |
| Inner Diameter of Stator(m) | 18,500(18,800) | 18,790 | 16,000 | 13,650 | 16,100 |
Its Buildings with Biggest Indices
Dam
The TGP dam is a concrete gravity one, made of 14.86 million m3 concrete, the biggest amount in the world. The maximum flood discharge capacity of the dam is 116 ,110 m3/s, biggest in the world.
Power Plant
The TGHP is of dam toe power house. The installed capacity of a unit and annual power generation of the TGHP are the biggest respectively. The transmission lines of two ±500 kV DC circuits and eleven 500 kV AC circuits are the biggest scale in the world.
Three Gorges ship lock
The following indices are the biggest in the world: total water head of 113 m, inland river ship lock of five stages, a lock chamber's effective dimension of 280 m×34 m×5 m (length × width × minimum water depth on the sill), inland river ship lock with capacity to accommodate 10000-tonnage fleets, maximum operating water head 49.5 m for a gate of its water exchange system, maximum water fill/discharge amount of 260000 m 3 , maximum side slope excavation of 170 m, in height and etc. The operating water head exceeds the world record.
Ship lift
Single-way and one-step vertical ship lift with counterweight is employed in TGP complex, consisting of upstream and downstream approach channels, upper and lower lock heads and ship chamber section with a total length of about 6000 m. The ship lock will allow a maximum 3000-tonnage ship passing through. The ship chamber has outline dimensions of 132 m (L) × 23.4 m (W) × 10 m (H) and effective water area in it is 120 m (L) × 18 m (W) × 3.5 m (D). The maximum lifting height is 113 m and total lifting weight about 12800 tons.
Compared with the ship lifts home and abroad that are built or under construction, TGP's ship loft ranks the first in the world in terms of the main technical parameters. Due to the large scale of construction, complicated operating conditions and high requirements in safety and reliability, TGP's ship lift also ranks the first among the world's ones built or under construction in terms of design, manufacture and difficult extent in construction.
The Relocation Population and Difficulty of Resettlement
According to a 1992 survey, the TGP reservoir impoundment will inundate 632 km 2 of land, including 24500 ha of farmland and citrus land, and affect habitats of 844100 people under submergence. It was planned to relocate a population of 1.13 million people. The relocation and resettlement of TGP reservoir migrants is a world record in scale and in difficulty.
Diagram of the TGP inundation area
Since the TGP was launched a decade ago, a few world records in hydropower construction were created, and a series of technology breakthrough were achieved, thanks to the continuous practice in science & technology renovation. They are outlined as follows:
River Close-off and Cofferdam in Deep Water
TGP river close-off was conducted on the main channel and the diversion channel, the difficulty is hardly seen in other water conservancy projects. The successful river close-offs on
Concrete Placement on the TGP Dam
High Slopes outside the Three Gorges Ship lock and Metal Structures
The double-way and five-step ship lock is characterized by the biggest water head, the most successive steps, the deepest excavation and the highest concreted side slope, and the highest and heaviest miter gate in the world.
The Design, Manufacture and Installation of the Generator Units
The TGP generator units have the features of large quantity, big capacity, big water head change. Due to their extremely important role in the power grid system, CTGPC has to ensure stability and efficiency of the turbines under high water head, and meanwhile, to take into account the operation performance under low water head. The installed capacity of one TGP unit is 700 MW, biggest in the world. Since the rated water head of TGP units is relatively low, the generators are designed to have maximum capacity of 840 M.VA. Therefore, the overall indices of TGP units set new world records.
River Close-off and Concrete Cut-off Wall Construction
The river close-off and the concrete cutoff wall construction are two key issues in building Phase-II rock-and-earth cofferdam.
River Close-off on the Main Channel
The TGP river close-off on the main channel features deep river, large inflow, intense construction, tight timetable, navigation during the close-off process, deep surface layer above the levee foundation, and other difficulties. The TGP dam is situated at the backwater region of the Gezhouba Reservoir, and during the close-off the maximum water depth at the riverbed was 60 m, a world record. It's crucial to prevent levee breakdown and keep the levee stable during the bank-off advance. So many hydraulic model tests, value calculations, and mechanism analysis were carried out to study this issue. The efforts led to conclusion that when water depth is reduced to 20 m, levee breakdown can be avoided. Accordingly, it was decided to adopt the program of pre-leveling, upstream single levee blocking, two directional bank-off advance, and downstream follow-up advance. Along with the gradual
inflow decrease, close-off levees successively advanced for preparation. At
The main channel close-off design, and the construction technology research and practice were awarded with the first prize for national science and technology achievement in 1999.
Deep Water Cofferdam and Concrete Cutoff Wall
The TGP Phase-II cofferdam was built to guarantee the year-around construction in the foundation pit during the TGP Phase II construction period. The scale of Phase-II cofferdam construction ranks top in the world. Since the water depth reaches 60 m, approximately 2/3 of the cofferdam was constructed underwater and it's very difficult to do the work. The geological condition is complicated and not suitable for building cutoff wall. The field condition only allows taking weathered grit as fill material, so the structure is loose in underwater dumping, its physical indices is bad and deformation will develop. Therefore the construction has to be conducted within a low-water season. The biggest difficulty of the Phase-II cofferdam is the construction of concrete cutoff wall. Dumping weathered grit into deep water and building two layers of 74 m flexible concrete cutoff walls in the sand-gravel cofferdam were achieved with good quality, seepage was measured to be only 65 L/s, quite rare in similar works.
For the first time, centrifugal model test was conducted in the construction of cofferdam to define that the density of dumped grit in water depth of 60 m should be 1.75 ～ 1.85 t/ m3 , and underwater slope angle should be 27°. The critical technical problem of deep water cofferdam design was solved. And it's the first time to make use of weathered grit and construction wastes and successfully produce flexible wall material that meets design requirement of the cutoff wall of the deep water cofferdam. Advanced construction equipment and auxiliaries were manufactured to solve the problem of granite layer level difference of more than 30 m, slope level of 70° ～ 80°, bedrock with double-directional slopes, and difficulty to make trench for filling with weathered grit. A new record, monthly constructing cutoff wall of 13000 m2 , was created. During dismantling, after all-around inspection, sampling, and analysis on the cofferdam and the cutoff wall, it was proved that the survey, research, design, and construction of the cofferdam are successful and serves as a reference to similar projects.
River Close-off on the Diversion Channel
It was not easy to hold steady the fill material on the slippery riverbed formed with artificial concrete during the river close-off on the diversion channel. And it was even more difficult than that on the main channel since the inflow of 10300 m 3 /s, the water fall of 4 meters, and water running speed of 7 m/s were bigger. The constructors applied steel-framed rock cages and alloy steel nets to roughen the bottom and to increase the friction of the riverbed, so that rock barrier was formed to reduce the difficulty of close-off and to ensure the stability of the fill materials. Two parallel levees were built to take the water fall of the diversion channel, the upstream
levee holding 2/3 of the water fall, the downstream one holding 1/3. On
Fast Concrete Placement Technology
Total concrete placement in the TGP construction amounts to 28×10 6 m3 , its quality requirement is strict, and the construction is difficult. Advanced equipment and fast concrete placement technology were applied to ensure the quality and the timetable. Concrete placement on the TGP dam started in 1998, and for the three successive years from 1999 to 2001, annual concrete placement amounted to more than 4 ×10 6 m3 ; the total of the three years added up to 14.09×10 6 m3 ; in 2000 new world records were created as follows: annual concrete placement of 5.48×10 6 m3 , monthly concrete placement of 553500 m3 , and daily concrete placement of 22000 m3 . The reason why the concrete placement for TGP dam was conducted at such a high speed and intensity lies in the following five aspects of technology breakthroughs.
Joint Construction Technology Based on Hi-tower Flatliners
In order to ensure high quality and high intensity placement, TGP constructors abandoned traditional concepts, and optimized the allocation of resources, and selected the construction scheme of application of Hi-tower Flatliners as the main equipment and subordinate application of gantry cranes, belt cranes, and cable cranes as auxiliaries. The traditional bucket placement was changed into continuous concrete production technology. The belt conveyor sent concrete from the batching plant to hi-tower Flatliner and then directly to the placement area, combining both horizontal and vertical transportation. At the same time, five concrete batching systems were equipped to produce 2500 m3 concrete on hourly basis.
A Whole System of Technology and Management for Fast Pouring
By fully implementing concrete placement technology design, a computerized supervision and control system for concrete production, conveying and pouring was developed to realize real-time monitoring, dynamic adjustment, and optimal dispatch for the whole process of concrete construction. Meantime, computer simulation system for concrete construction was developed to address the complicated situation of concrete placement.
Raw Materials and Gradation Optimization of Concrete
By applying high-quality efficient water-reducing agent which was mixed with Grade I fly ash, water consumption for Gradation IV concrete, which was made with artificial granite aggregate, was cut from 110 kg/m 3 to about 90 kg/m3 . The approach of lower water-cement ratio and more fly ash content helped to more effectively upgrade the durability of concrete. Mid-heat dam cement 525#, which features compensation for contraction, was applied to reduce contraction and deformation of concrete and to eliminate the risk of cracks developing in the concrete.
Secondary Air Cooling Technology
With repeated tests to address the TGP characteristics and the pre-cooling requirement of concrete, secondary air cooling of aggregates were applied for the first time. The new point is to replace conventional water cooling of the ground aggregates with air cooling. Cold air closed circulating system, including the efficient cooling fan and the corresponding air feeding and distributing equipment, helps to cool down aggregate continuously.
Overall Temperature Control of the Concrete
On the basis of extensively analyzing present temperature control measures taken in the projects home and abroad, overall temperature control technology for whole process was implemented for the first time in an all-around way and at high standard and large capacity. The temperature control measures includes selecting good-quality raw materials, optimizing concrete gradation, controlling concrete exit temperature and pouring temperature, cooling with running water, surface temperature keeping, and curing with running water, and etc. Especially in summer, high-tower flatliner helps to place concrete in constraint areas of the concrete dam at high speed and intensity, which is the first practice of this kind in the world.
6252 monitoring devices of various kinds embedded in every corner of the dam indicate that deformation of the dam foundation is less than 1mm, foundation seepage is only 1/10 of the design value, and horizontal shift and stress are within the design scope, completely meeting the design requirement. The quality of the dam is excellent..
Environmental Benefit of Three Gorges Project
| Three Gorges project will not only produce huge economic benefit, but also play great role in improving the ecological environment of First Target of Three Gorges Project is Flood Control. |
The project can effectively adjust the upstream flood of Yangtze River, which will assure a flood control standard of the Jingjiang section, a downstream reach to Three Gorges of Yangtze River, arise from currently preventing 10-year flood to controlling 100-year flood. Even in case of a rare occurrence of 1000-year flood, mass damages or injuries can still be prevented. At the same time, social problems such as environmental deterioration and epidemics related to the flood or flood diversion can also be avoided. Thus the project will protect 1.5 million hectare of farmland and towns, and 15 million of people from flood damage at Jianghan Plain and
| Three Gorges Power Plant will Provide Clean Energy. |
Compared to the coal-fired power stations with equivalent electricity generation, Three Gorges Power Plant will decrease emission of 100 million tons of CO2, 2 million tons of SO2, 0.37 million tons of nitrogen oxide and a lot of waste water and solid waste. It will bring a great benign influence in improvement of environment, especially preventing acid rain and greenhouse effect in East and
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| Other Benefit of T hree Gorges Project The Three Gorges reservoir, after the project is completed, will improve the weather in this area, be favorable for agriculture, and improve water quality in the mid and lower reach, which will relieve the invasion of saline tide in the river's mouth to |
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| Protection of Water Quality | |
| The reservoir has a mixed influence on the water quality of |
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| According to the Gazette of Ecological and Environmental Monitoring published by the State Environmental Protection Administration of China in 2002, the water quality of the Yangtze in TGP area still kept not bad in 2002, most better than or at class III, though industrial wastes directly emitted to the River Yan g tze increased by 23.8% than in 2001, the environmental quality of the project areas kept good. Environmental monitoring in 2003 indicates that overall management of water quality in TGP area has obtained made initial achievement, with a decrease ratio at class IV and increase at class II and III compared to the period before impoundment. | |
| Possible Earthquake and Bank Stability due to the Reservoir | |
| | The possible earthquake issue due to Three Gorges reservoir has been emphasized by the government for a long time, and extensive researches have been made on the issue involved in the rock, geologic structure, osmosis, etc. A 300~800 m deep-hole earth stress observation is carried out at dam and reservoir site and the earthquake intensive observation is made on some fracture zones around the dam. According to the researches, the geologic structure is stable, and has no geological background for a future heavy earthquake.
The earthquake monitoring indicates that earthquake activities may increase after the reservoir operates, but that of higher than class II is little, and have no damages to the reservoir area, nor to the dam that is designed to be able to withstand Class VII earthquake. |
| At the same time, the state adopted other engineering methods to protect the environment, to control the soil and water losses, which will decrease sediment inflow to Latest result of monitoring indicates that the content of sediment in the water has a trend of decreasing, and soil and water losses in Three Gorges area goes down at about 1% per year. |
In 1918, Mr. Sun Yat-Sen suggested, in his book Strategy for State, Part II: Industrial Plans , a scheme to “improve the upstream from here”, that is, “a dam should be set here to let ships go downstream and use the water resource as power.”
In May 1945, Dr. John Lucian Savage, a famous American expert in dam construction arrived in Three Gorges and put forward his Preliminary Report on Development Plans of Three Gorges .
In Feb 1950, Changjiang Water Resource Commission, a special governmental organization, was founded for the comprehensive management of the
In 1955, a comprehensive planning of
In
In Feb 1982, Qian Zhengying communicated the instructions from the central government that TGP be listed in the recent national plan. And on 24, Nov, Deng Xiaoping, the former leader of
In Feb- March 1989, the Leading Group for Three Gorges Project Argumentation reviewed and approved the revised Feasibility Report of Three Gorges Project with normal storage level of 175 m , which indicates that the re-argumentation of the project concluded.
On 3 rd April 1992, The Resolution to Construction of Three Gorges Project was adopted at the 5 th meeting of the Seventh People's Congress , which indicates that the project entered in to the executive process from legislative process.
On
On
On 29 July 1993, the State Council TGP Construction Committee approved the Report of Preliminary Design of the Three Gorges Project forwarded by Changjiang Water Resource Commission the second committee meeting, which indicates the project entered into the overall preparation stage for construction.
On
On On On
On 1 st June 2003, the reservoir began its storage, the water reached at 135m on 10 June and at 139m on 5 November.
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Till
Three Gorges
Lead Author: Cutler J. Cleveland (other articles)
Article Topics: Energy, Environmental history and Geography of Energy
This article has been reviewed and approved by the following Topic Editor: Brian Black (other articles)
Last Updated:
Map of the
Three Gorges
On
The reservoir is 630km long and an average of 1.3km wide, while the dam wall is 185m high and almost as deep, stretching 2.3km across the valley. About 27 million cubic meters of concrete have gone into the structure since work began; that's more than eight times as much as has been poured into the Hoover dam on the Colorado River and twice the amount of concrete in the Itaipú dam. The Three Gorges project has been engineered to store over 5 trillion gallons of water and to withstand an earthquake of 7.0 on the Richter scale.
There about 50,000 other dams on the
Benefits from the Three Gorges Project
To
Transportation of people and goods will be greatly enhanced. The reservoir will allow 10,000-ton freighters to enter the nation's interior, which currently limits access to boats under 1,500 tons. Vessels will be able to navigate from
The dam is also intended to provide major flood control benefits. Historically, the population in the middle and lower reaches of the
The government also notes that the dam's power generation potential of 84.7BkWh/yr is the energy equivalent of burning 50 million tons of coal or 25 million tons of crude oil. Thus, the switch to cleaner hydroelectric power would have the effect of cutting 100 million tons of carbon dioxide, up to two million tons of sulfur dioxide, ten thousand tons of carbon monoxide, 370,000 tons of nitrogen oxide, and 150,000 tons of particulates annually from the atmosphere.
Social and Environmental Concerns
Critics of the Three Gorges project argue that the project’s costs may outweigh the benefits, the latter of which have allegedly been exaggerated by the government. The Three Gorges Dam project has become a symbol of national unity and strength for the ruling communist party. As a result, critics charge that many of the controversies surrounding the project are glossed over or ignored. In an address to the engineers of the dam, then Premier Li Peng, himself a power engineer by training, said the scale of the project was proof to the world of
Foreign perception of the project has suffered from the reputation of its principal proponent in
Resettlement is a major source of controversy. More than 1.2 million will have to be resettled before the Yangtze valley is submerged. Entire villages and parts of major cities have been relocated. Critics claim that those forced out of the area have not been adequately compensated, particularly as the land they lost was highly fertile. But the government insists that the scale of its compensation package demonstrates its commitment to helping those affected improve their standard of living.
Upwards of 1,000 archeological sites will be submerged beneath the reservoir. Ancestral burial grounds and centuries-old temples, fossil remains, and archeological sites dating as far back as the Paleolithic Age risk being lost from public access and scholarly pursuit if they are not unearthed and relocated before the waters rise. The government has taken measures that it claims will mitigate these losses.
There is also concern about the impact the project will have on biological diversity. The baiji dolphin, the ancient river sturgeon and the finless porpoise depend on the Yangtze for their survival. The population of Siberian cranes in
Yangtze Delta.
Sedimentation of the reservoir is also a serious challenge. The flow of the Yangtze carries with it the fifth-largest sediment discharge of any river in the world, equivalent to about 4 percent of all river-borne sediment discharged to all the oceans of the world. Sediment buildup behind the dam and throughout the reservoir would effect the overall storage capacity of the reservoir. The loss of storage capacity would directly result in a decrease in project’s flood control capability. The high rate of sediment deposit has already affected the diversion channel and is expected to compromise operation of the dam sooner and more seriously than had been anticipated.
The
Barber, Margaret, and Gráinne Ryder, Editors. Damming The Three Gorges: A Critique of the Three Gorges Water Control Project Feasibility Study.
Information from the Chinese Embassy regarding Three Gorges
Citation
Cleveland, Cutler (Lead Author); Brian Black (Topic Editor). 2008. "Three Gorges
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