Three Gorges Dam | Wikipedia audio article

The Three Gorges Dam is a hydroelectric gravity
dam that spans the Yangtze River by the town of Sandouping, in Yiling District, Yichang,
Hubei province, China. The Three Gorges Dam has been the world’s
largest power station in terms of installed capacity (22,500 MW) since 2012. In 2014, the dam generated 98.8 terawatt-hours
(TWh) and had the world record, but was surpassed by the Itaipú Dam, which set the new world
record in 2016, producing 103.1 TWh.Except for the locks, the dam project was completed
and fully functional as of July 4, 2012, when the last of the main water turbines in the
underground plant began production. The ship lift was complete in December 2015. Each main water turbine has a capacity of
700 MW. The dam body was completed in 2006. Coupling the dam’s 32 main turbines with two
smaller generators (50 MW each) to power the plant itself, the total electric generating
capacity of the dam is 22,500 MW.As well as producing electricity, the dam is intended
to increase the Yangtze River’s shipping capacity and reduce the potential for floods downstream
by providing flood storage space. China regards the project as monumental as
well as a success socially and economically, 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, displaced some 1.3 million people, and had caused significant ecological
changes including an increased risk of landslides. The dam has been controversial both domestically
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 by
Chiang Kai-shek, began preliminary work on plans in the Three Gorges. In 1939, 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 China. In 1944, the United States Bureau of Reclamation
head 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 employ
a unique method for moving ships; the ships would move into locks located at the lower
and upper ends of the dam and then cranes with cables would move the ships from one
lock to the next. In the case of smaller water craft, groups
of craft would be lifted together for efficiency. It is not known whether this solution was
considered for its water-saving performance or because the engineers thought the difference
in height between the river above and below the dam too great for alternative methods. 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 takeover, Mao Zedong
supported the project, but began the Gezhouba Dam project nearby 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 abstained,
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, delayed full operation until May 2012. The ship lift was completed in 2015. The dam had raised the water level in the
reservoir to 172.5 m (566 ft) above sea level by the end of 2008 and the designed maximum
level of 175 m (574 ft) by October 2010.==Composition and dimensions==Made of concrete and steel, the dam is 2,335
m (7,661 ft) long and the top of the dam is 185 m (607 ft) above sea level. The project used 27.2×10^6 m3 (35.6×10^6
cu yd) of concrete (mainly for the dam wall), used 463,000 T of steel (enough to build 63
Eiffel Towers), and moved about 102.6×10^6 m3 (134.2×10^6 cu yd) of earth. The concrete dam wall is 181 m (594 ft) high
above the rock basis. When the water level is at its maximum of
175 m (574 ft) above sea level, 110 m (361 ft) higher than the river level downstream,
the dam reservoir is on average about 660 km (410 mi) in length and 1.12 km (3,675 ft)
in width. It contains 39.3 km3 (31,900,000 acre⋅ft)
of water and has a total surface area of 1,045 km2 (403 sq mi). On completion, the reservoir flooded a total
area of 632 km2 (244 sq mi) of land, compared to the 1,350 km2 (520 sq mi) of reservoir
created by the Itaipu Dam.==Economics==
The government estimated that the Three Gorges Dam project would cost 180 billion yuan (US$22.5
billion). By the end of 2008, spending had reached 148.365
billion yuan, among which 64.613 billion yuan was spent on construction, 68.557 billion
yuan on relocating affected residents, and 15.195 billion yuan on financing. It was estimated in 2009 that the construction
cost would be recovered when the dam had generated 1,000 terawatt-hours (3,600 PJ) of electricity,
yielding 250 billion yuan. Full cost recovery was thus expected to occur
ten years after the dam started full operation, but the full cost of the Three Gorges Dam
was recovered by December 20, 2013.Funding sources include the Three Gorges Dam Construction
Fund, profits from the Gezhouba Dam, loans from the China Development Bank, loans from
domestic and foreign commercial banks, corporate bonds, and revenue from both before and after
the dam is fully operational. Additional charges were assessed as follows:
Every province receiving power from the Three Gorges Dam had to pay ¥7.00 per MWh extra. Other provinces had to pay an additional charge
of ¥4.00 per MWh. The Tibet Autonomous Region pays no surcharge.==Power generation and distribution=====
Generating capacity===Power generation is managed by China Yangtze
Power, a listed subsidiary of China Three Gorges Corporation (CTGC)—a Central Enterprise
SOE administered by SASAC. The Three Gorges Dam is the world’s largest
capacity hydroelectric power station with 34 generators: 32 main generators, each with
a capacity of 700 MW, and two plant power generators, each with capacity of 50 MW, making
a total capacity of 22,500 MW. Among those 32 main generators, 14 are installed
in the north side of the dam, 12 in the south side, and the remaining six in the underground
power plant in the mountain south of the dam. Annual electricity generation in 2015 was
87 TWh, which is 20 times more than the Hoover Dam.===Generators===
The main generators weigh about 6,000 tonnes each and are designed to produce more than
700 MW of power. The designed head of the generator is 80.6
meters (264 ft). The flow rate varies between 600–950 cubic
metres per second (21,000–34,000 cu ft/s) depending on the head available. The greater the head, the less water needed
to reach full power. Three Gorges uses Francis turbines. Turbine diameter is 9.7/10.4 m (VGS design/Alstom’s
design) and rotation speed is 75 revolutions per minute. This means that in order to generate power
at 50 Hz, the generator rotors have 80 poles. Rated power is 778 MVA, with a maximum of
840 MVA and a power factor of 0.9. The generator produces electrical power at
20 kV. The electricity generated is then stepped-up
to 500 kV for transmission at 50 Hz. The outer diameter of the generator stator
is 21.4/20.9 m. The inner diameter is 18.5/18.8 m. The stator, the biggest of its kind, is 3.1/3
m in height. Bearing load is 5050/5500 tonnes. Average efficiency is over 94%, and reaches
96.5%. The generators were manufactured by two joint
ventures: one of them Alstom, ABB Group, Kvaerner, and the Chinese company Harbin Motor; the
other Voith, General Electric, Siemens (abbreviated as VGS), and the Chinese company Oriental
Motor. The technology transfer agreement was signed
together with the contract. Most of the generators are water-cooled. Some newer ones are air-cooled, which are
simpler in design and manufacture and are easier to maintain.===Generator installation progress===
The first north side main generator (No. 2) started on July 10, 2003; the north side became
completely operational September 7, 2005, with the implementation of generator No. 9. Full power (9,800 MW) was only reached on
October 18, 2006, after the water level reached 156 m.The 12 south side main generators are
also in operation. No. 22 began operation on June 11, 2007, and
No. 15 started up on October 30, 2008. The sixth (No. 17) began operation on December
18, 2007, raising capacity to 14.1 GW, finally surpassing Itaipu (14.0 GW), to become the
world’s largest hydro power plant by capacity.As of May 23, 2012, when the last main generator,
No. 27, finished its final test, the six underground main generators are also in operation, raising
capacity to 22.5 GW. After nine years of construction, installation
and testing, the power plant is now fully operational.===Output milestones===By August 16, 2011, the plant had generated
500 TWh of electricity. In July 2008 it generated 10.3 TWh of electricity,
its first month over 10 TWh. On June 30, 2009, after the river flow rate
increased to over 24,000 m3, all 28 generators were switched on, producing only 16,100 MW
because the head available during flood season is insufficient. During an August 2009 flood, the plant first
reached its maximum output for a short period.During the November to May dry season, power output
is limited by the river’s flow rate, as seen in the diagrams on the right. When there is enough flow, power output is
limited by plant generating capacity. The maximum power-output curves were calculated
based on the average flow rate at the dam site, assuming the water level is 175 m and
the plant gross efficiency is 90.15%. The actual power output in 2008 was obtained
based on the monthly electricity sent to the grid.The Three Gorges Dam reached its design-maximum
reservoir water level of 175 m (574 ft) for the first time on October 26, 2010, in which
the intended annual power-generation capacity of 84.7 TWh was realized. In 2012, the dam’s 32 generating units generated
a record 98.1 TWh of electricity, which accounts for 14% of China’s total hydro generation.===Distribution===
The State Grid Corporation and China Southern Power Grid paid a flat rate of ¥250 per MWh
(US$35.7) until July 2, 2008. Since then, the price has varied by province,
from ¥228.7–401.8 per MWh. Higher-paying customers, such as Shanghai,
receive priority. Nine provinces and two cities consume power
from the dam.Power distribution and transmission infrastructure cost about 34.387 billion Yuan. Construction was completed in December 2007,
one year ahead of schedule.Power is distributed over multiple 500 kilovolt (kV) transmission
lines. Three direct current (DC) lines to the East
China Grid carry 7,200 MW: Three Gorges – Shanghai (3,000 MW), HVDC Three Gorges – Changzhou
(3,000 MW), and HVDC Gezhouba – Shanghai (1,200 MW). The alternating current (AC) lines to the
Central China Grid have a total capacity of 12,000 MW. The DC transmission line HVDC Three Gorges
– Guangdong to the South China Grid has a capacity of 3,000 MW.The dam was expected
to provide 10% of China’s power. However, electricity demand has increased
more quickly than previously projected. Even fully operational, on average, it supports
only about 1.7% of electricity demand in China in the year of 2011, when the Chinese electricity
demand reached 4692.8 TWh.==Environmental impact=====
Emissions===According to the National Development and
Reform Commission of China, 366 grams of coal would produce 1 kWh of electricity during
2006. At full power, Three Gorges reduces coal consumption
by 31 million tonnes per year, avoiding 100 million tonnes of greenhouse gas emissions,
millions of tonnes of dust, one million tonnes of sulfur dioxide, 370,000 tonnes of nitric
oxide, 10,000 tonnes of carbon monoxide, and a significant amount of mercury. Hydropower saves the energy needed to mine,
wash, and transport the coal from northern China. From 2003 to 2007, power production equaled
that of 84 million tonnes of standard coal, reducing carbon dioxide by 190 million tonnes,
sulfur dioxide by 2.29 million tonnes, and nitrogen oxides by 980,000 tonnes.The dam
increased the Yangtze’s barge capacity sixfold, reducing carbon dioxide emission by 630,000
tonnes. From 2004 to 2007, a total of 198 million
tonnes of goods passed through the ship locks. Compared to using trucking, barges reduced
carbon dioxide emission by ten million tonnes and lowered costs by 25%.===Erosion and sedimentation===
Two hazards are uniquely identified with the dam. One is that sedimentation projections are
not agreed upon, and the other is that the dam sits on a seismic fault. At current levels, 80% of the land in the
area is experiencing erosion, depositing about 40 million tons of sediment into the Yangtze
annually. Because the flow is slower above the dam,
much of this sediment will now settle there instead of flowing downstream, and there will
be less sediment downstream. The absence of silt downstream has three effects: Some hydrologists expect downstream riverbanks
to become more vulnerable to flooding. Shanghai, more than 1,600 km (990 mi) away,
rests on a massive sedimentary plain. The “arriving silt—so long as it does arrive—strengthens
the bed on which Shanghai is built… the less the tonnage of arriving sediment the
more vulnerable is this biggest of Chinese cities to inundation…” Benthic sediment buildup causes biological
damage and reduces aquatic biodiversity.===Landslides===
Erosion in the reservoir, induced by rising water, causes frequent major landslides that
have led to noticeable disturbance in the reservoir surface, including two incidents
in May 2009 when somewhere between 20,000 and 50,000 cubic metres (26,000 and 65,000
cu yd) of material plunged into the flooded Wuxia Gorge of the Wu River. Also, in the first four months of 2010, there
were 97 significant landslides.===Waste management===The dam catalyzed improved upstream wastewater
treatment around Chongqing and its suburban areas. According to the Ministry of Environmental
Protection, as of April 2007, more than 50 new plants could treat 1.84 million tonnes
per day, 65% of the total need. About 32 landfills were added, which could
handle 7,664.5 tonnes of solid waste every day. Over one billion tons of wastewater are released
annually into the river, which was more likely to be swept away before the reservoir was
created. This has left the water looking stagnant,
polluted and murky.===Forest cover===
In 1997, the Three Gorges area had 10% forestation, down from 20% in the 1950s.Research by the
United Nations Food and Agriculture Organization suggested that the Asia-Pacific region would,
overall, gain about 6,000 km2 (2,300 sq mi) of forest by 2008. That is a significant change from the 13,000
km2 (5,000 sq mi) net loss of forest each year in the 1990s. This is largely due to China’s large reforestation
effort. This accelerated after the 1998 Yangtze River
floods convinced the government that it must restore tree cover, especially in the Yangtze’s
basin upstream of the Three Gorges Dam.===Wildlife===
Concerns about the potential wildlife impact of the dam predate the National People’s Congress’s
approval in 1992. This region has long been known for its rich
biodiversity. It is home to 6,388 species of plants, which
belong to 238 families and 1508 genera. Of these plant species, 57 percent are endangered. These rare species are also used as ingredients
in traditional Chinese medicines. Already, the percentage of forested area in
the region surrounding the Three Gorges Dam has dropped from twenty percent in 1950 to
less than ten percent as of 2002, negatively affecting all plant species in this locality. The region also provides habitats to hundreds
of freshwater and terrestrial animal species. Freshwater fish are especially affected by
dams due to changes in the water temperature and flow regime. Many other fish are hurt in the turbine blades
of the hydroelectric plants as well. This is particularly detrimental to the ecosystem
of the region because the Yangtze River basin is home to 361 different fish species and
accounts for twenty-seven percent of all endangered freshwater fish species in China. Other aquatic species have been endangered
by the dam, particularly the baiji, or Chinese river dolphin, now extinct. In fact, Government Chinese scholars even
claim that the Three Gorges Dam directly caused the extinction of the baiji.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 contributed to the functional extinction
of the baiji Yangtze river dolphin. Though it was close to this level even at
the start of construction, the dam further decreased its habitat and increased ship travel,
which are among the factors causing what will be its ultimate demise. In addition, populations of the Yangtze sturgeon
are guaranteed to be “negatively affected” by the dam.===Terrestrial impact===
In 2010, NASA scientists calculated that shift of water mass stored by the dams would increase
the length of the Earth’s day by 0.06 microseconds and make the Earth slightly more round in
the middle and flat on the poles.==Floods, agriculture, industry==
An important function of the dam is to control flooding, which is a major problem for the
seasonal river of the Yangtze. Millions of people live downstream of the
dam, with many large, important cities like Wuhan, Nanjing, and Shanghai situated adjacent
to the river. Plenty of farm land and China’s most important
industrial area are built beside the river. The reservoir’s flood storage capacity is
22 cubic kilometres (5.3 cu mi; 18,000,000 acre⋅ft). This capacity will reduce the frequency of
major downstream flooding from once every 10 years to once every 100 years. The dam is expected to minimize the effect
of even a “super” flood. In 1954, the river flooded 193,000 km2 (74,500
sq mi), killing 33,169 people and forcing 18,884,000 people to move. The flood covered Wuhan, a city of eight million
people, for over three months, and the Jingguang Railway was out of service for more than 100
days. The 1954 flood carried 50 cubic kilometres
(12 cu mi) of water. The dam could only divert the water above
Chenglingji, leaving 30 to 40 km3 (7.2 to 9.6 cu mi) to be diverted. Also, the dam cannot protect against some
of the large tributaries downstream, including the Xiang, Zishui, Yuanshui, Lishui, Hanshui,
and the Gan. In 1998, a flood in the same area caused billions
of dollars in damage; 2,039 km2 (787 sq mi) of farm land were flooded. The flood affected more than 2.3 million people,
killing 1,526. In early August 2009, the largest flood in
five years passed through the dam site. The dam limited the water flow to less than
40,000 cubic metres (1,400,000 cu ft) per second, raising the upstream water level from
145.13 m (476.1 ft) on August 1, 2009, to 152.88 m (501.6 ft) on August 8, 2009. A full 4.27 km3 (1.02 cu mi) of flood water
was captured and the river flow was cut by as much as 15,000 m3 (530,000 cu ft) per second.The
dam discharges its reservoir during the dry season between December and March every year. This increases the flow rate of the river
downstream, and provides fresh water for agricultural and industrial usage. It also improves shipping conditions. The water level upstream drops from 175 to
145 m (574 to 476 ft), preparing for the rainy season. The water also powers the Gezhouba Dam downstream. Since the filling of the reservoir in 2003,
the Three Gorges Dam has supplied an extra 11 km3 (2.6 cu mi) of fresh water to downstream
cities and farms during the dry season. During the 2010 South China floods in July,
inflows at the Three Gorges Dam reached a peak of 70,000 m3/s (2,500,000 cu ft/s), exceeding
the peak during the 1998 Yangtze River Floods. The dam’s reservoir rose nearly 3 m (9.8 ft)
in 24 hours and reduced the outflow to 40,000 m3/s (1,400,000 cu ft/s) in discharges downstream,
effectively alleviating serious impacts on the middle and lower river.==Navigating the dam=====
Locks===The installation of ship locks is intended
to increase river shipping from ten million to 100 million tonnes annually, as a result
transportation costs will be cut between 30 and 37%. Shipping will become safer, since the gorges
are notoriously dangerous to navigate. Ships with much deeper draft will be able
to navigate 2,400 kilometres (1,500 mi) upstream from Shanghai all the way to Chongqing. It is expected that shipping to Chongqing
will increase fivefold.There are two series of ship locks installed near the dam (30°50′12″N
111°1′10″E). Each of them is made up of five stages, with
transit time at around four hours. Maximum vessel size is 10,000 tons. The locks are 280 m long, 35 m wide, and 5
m deep (918 × 114 × 16.4 ft). That is 30 m (98 ft) longer than those on
the St Lawrence Seaway, but half as deep. Before the dam was constructed, the maximum
freight capacity at the Three Gorges site was 18.0 million tonnes per year. From 2004 to 2007, a total of 198 million
tonnes of freight passed through the locks. The freight capacity of the river increased
six times and the cost of shipping was reduced by 25%. The total capacity of the ship locks is expected
to reach 100 million tonnes per year.These locks are staircase locks, whereby inner lock
gate pairs serve as both the upper gate and lower gate. The gates are the vulnerable hinged type,
which, if damaged, could temporarily render the entire flight unusable. As there are separate sets of locks for upstream
and downstream traffic, this system is more water efficient than bi-directional staircase
locks.===Ship lift===In addition to the canal locks, there is a
ship lift, a kind of elevator for vessels. The ship lift can lift ships of up to 3,000
tons. The vertical distance traveled is 113 m (371
ft), and the size of the ship lift’s basin is 120 m × 18 m × 3.5 m (394 ft × 59 ft
× 11 ft). The ship lift takes 30 to 40 minutes to transit,
as opposed to the three to four hours for stepping through the locks. One complicating factor is that the water
level can vary dramatically. The ship lift must work even if water levels
vary by 12 meters (39 ft) on the lower side, and 30 m (98 ft) on the upper side. The ship lift’s design uses a helical gear
system, to climb or descend a toothed rack.The ship lift was not yet complete when the rest
of the project was officially opened on May 20, 2006. In November 2007, it was reported in the local
media that construction of the ship lift started in October 2007.In February 2012, Xinhua reported
that the four towers that are to support the ship lift had almost been completed.The report
said the towers had reached 189 m (620 ft) of the anticipated 195 m (640 ft), the towers
would be completed by June 2012 and the entire shiplift in 2015. As of May 2014, the ship lift was expected
to be completed by July 2015. It was tested in December 2015 and announced
complete in January 2016. Lahmeyer, the German firm that designed the
ship lift, said it will take a vessel less than an hour to transit the lift. An article in Steel Construction says the
actual time of the lift will be 21 minutes. It says that the expected dimensions of the
3,000 tonnes (3,000,000 kg) passenger vessels the ship lift’s basin was designed to carry
will be 84.5 by 17.2 by 2.65 metres (277.2 ft × 56.4 ft × 8.7 ft). The moving mass (including counterweights)
is 34,000 tonnes. The trials of elevator finished in July 2016,
the first cargo ship was lifted in July 15, the lift time comprised 8 minutes.Shanghai
Daily reported that the first operational use of the lift was on September 18, 2016,
when limited “operational testing” of the lift began.===Portage railways===
Plans also exist for the construction of short portage railways bypassing the dam area altogether. Two short rail lines, one on each side of
the river, are to be constructed. The 88-kilometre (55 mi) long northern portage
railway (北岸翻坝铁路) will run from the Taipingxi port facility (太平溪港)
on the northern side of the Yangtze, just upstream from the dam, via Yichang East Railway
Station to the Baiyang Tianjiahe port facility in Baiyang Town (白洋镇), below Yichang. The 95-kilometre (59 mi) long southern portage
railway (南岸翻坝铁路) will run from Maoping (upstream of the dam) via Yichang
South Railway Station to Zhicheng (on the Jiaozuo–Liuzhou Railway).In late 2012, preliminary
work started along both future railway routes.==Relocation of residents==
Though the large size of the reservoir caused huge relocation upstream, it was considered
justified by the flood protection it provides for communities downstream. As of June 2008, China relocated 1.24 million
residents (ending with Gaoyang in Hubei Province) as 13 cities, 140 towns and 1350 villages
either flooded or were partially flooded by the reservoir [A_2-M:CR3-1HP:S-15], about
1.5% of the province’s 60.3 million and Chongqing Municipality’s 31.44 million population. About 140,000 residents were relocated to
other provinces.Relocation was completed on July 22, 2008. Some 2007 reports claimed that Chongqing Municipality
will encourage an additional four million people to move away from the dam to the main
urban area of Chongqing by 2020. However, the municipal government explained
that the relocation is due to urbanization, rather than the dam, and people involved included
other areas of the municipality.Allegedly, funds for relocating 13,000 farmers around
Gaoyang disappeared after being sent to the local government, leaving residents without
compensation.==Other effects=====Culture and aesthetics===
The 600 km (370 mi) long reservoir flooded some 1,300 archaeological sites and altered
the appearance of the Three Gorges as the water level rose over 91 m (300 ft). Cultural and historical relics are being moved
to higher ground as they are discovered, but the flooding inevitably covered undiscovered
relics. Some sites could not be moved because of their
location, size, or design. For example, the hanging coffins site high
in the Shen Nong Gorge is part of the cliffs.===National security===
The United States Department of Defense reported 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.”The
notion that the military in Taiwan would seek to destroy the dam provoked an angry response
from the mainland Chinese 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.”The Three
Gorges Dam is a steel-concrete gravity dam. The water is held back by the innate mass
of the individual dam sections. As a result, damage to an individual section
should not affect other parts of the dam. However, damage to the entire dam through
means such as missiles could cause flooding along a large area of the Yangtze River due
to overflow spillage.===Structural integrity===
Days after the first filling of the reservoir, around 80 hairline cracks were observed in
the dam’s structure. The submerged spillway gates of the dam might
pose a risk of cavitation, similar to that which severely damaged the poorly designed
and cavitating spillways of the Glen Canyon Dam in the US state of Arizona, which was
unable to properly withstand the Colorado river floods of 1983. However, 163,000 concrete units of the Three
Gorges dam all passed quality testing and the deformation was within design limits. An experts group gave the project overall
a good quality rating.==Upstream dams==In order to maximize the utility of the Three
Gorges Dam and cut down on sedimentation from the Jinsha River, the upper course of the
Yangtze River, authorities plan to build a series of dams on the Jinsha, including Wudongde
Dam, Baihetan Dam, along with the now completed Xiluodu and Xiangjiaba dams. The total capacity of those four dams is 38,500
MW, almost double the capacity of the Three Gorges. Baihetan is preparing for construction and
Wudongde is seeking government approval. Another eight dams are in the midstream of
the Jinsha and eight more upstream of it.==See also==Baiheliang Underwater Museum
Energy policy of China List of largest power stations in the world
List of largest hydroelectric power stations List of power stations in China
List of dams and reservoirs in China Three Gorges Museum
Liang Weiyan, one of the leading engineers who designed the water turbines for the dam

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