Gezhouba Dam

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Gezhouba
Gezhouba Dam
Gezhouba Dam
Location: Hubei , PR China
Tributaries: Yangtze River
Drain: Yangtze River
Major cities nearby: Yichang
Gezhouba (China)
Gezhouba
Coordinates 30 ° 44 ′ 20 "  N , 111 ° 16 ′ 20"  E Coordinates: 30 ° 44 ′ 20 "  N , 111 ° 16 ′ 20"  E
Data on the structure
Lock type: Concrete gravity dam
Construction time: 1970-1988
Height above valley floor: about 35 m
Height above foundation level : 47 m
Height of the structure crown: 70 m above sea level NN
Building volume: 9.8 million m³
Crown length: 2,595 m
Power plant output: 2,715 MW
Data on the reservoir
Altitude (at congestion destination ) 66 m above sea level NN
Reservoir width 300 m to 2,200 mdep1
Storage space 1,580,000,000 m³ = 1.58 km³
Design flood : 110,000 m³ / s
Yangtze longitudinal profile upstream.JPG
Elevation profile of dams on the Yangtze River

The Gezhouba Dam (Chinese 长江 葛洲坝 水利 枢纽 工程, English Gezhouba Dam or Gezhouba Water Control Project) is a dam on the Yangtze River with a hydroelectric power station and three locks . It was built near Yichang in Hubei Province in central China and is 38 km below the Three Gorges Dam .

The Gezhouba Dam is the first hydropower plant to be built on the Yangtze River. After commissioning in 1988, it was also the most powerful in China.

Gezhouba is one of the 100 largest hydropower plants in the world. It has a total output of 2,715 megawatts and an annual electricity production of 14,100 GWh. The facility is operated by the China Three Gorges Corporation (CTG).

Project

Satellite image of the Gezhouba Reservoir. The dam is in the right third of the picture. On the left is the Three Gorges Dam

prehistory

Many of China's great rulers had the desire to use the Yangtze to generate energy. Sun Yat-sen expressed his thoughts in this regard as early as 1919. After the Second World War , the American Bureau of Reclamation was commissioned with a project study for a dam near the three gorges. Because of the Chinese civil war , the project could not be realized. Mao Zedong tried to build the dam in 1958, but failed because of the high costs.

In 1969, the Hubei provincial government made an attempt to revive the project. But now it was rejected by Mao Zedong for political and military reasons. As a replacement, however, a smaller dam was approved 38 km further downstream near the city of Yichang. Thus, on December 30, 1970, the construction of the Gezhouba Dam began.

Construction progress

In 1970 the "China Gezhouba Group Corporation" (CGGC), which was subordinate to the State Asset Supervision and Administrative Commission, was founded and entrusted with the construction of the Gezhouba plants.

The gravity dam , the two hydropower plants and the three locks were built between 1970 and 1988. Two power stations with a total of 21 turbines with a total output of 2.715 gigawatts were built behind the dam. The main power plant on the right side is equipped with 14 turbines and the power plant on the left side with 7 turbines. In the middle of the dam is the flood overflow, consisting of 27 openings.

After passing the Nanjing Pass, the Yangtze River widens from 300 m to the dam to around 2,200 m. In front of the barrier are the two islands of Gezhouba and Xiba, which were created by sediment deposition . The river is divided into three arms by the islands. The ship locks are on the right and left arms. Lock 1 is on the right arm of the river. Lock 2 is on the left arm on the right. Both are 280 m long, 34 m wide and 5 m deep. You can let ships of up to 10,000 tons pass through. Lock 3 is on the left side of the left arm. It is 120 m long, 18 m wide and 3.5 m deep. It can carry cargo or passenger ships of up to 3,000 tons. In 1980, lock 3 was put into operation as the first ship lock on the Yangtze.

costs

The total cost of the Gezhouba project was approximately $ 24.5 billion.

Technical specifications

Gezhouba dam, ships going downhill
  • Type of construction: gravity dam made of concrete
  • Construction time:
    • Start of construction on December 30, 1970
    • Construction work on the dam, ship locks and power plants completed on December 10, 1988
  • Length of the barrier structure: 2,595 m including lock systems
  • Height of the barrier structure above the foundation base: 47 m
  • Height of the barrier structure above the valley floor: approx. 35 m
  • Height of the top of the wall: 70 m above sea level
  • Flood overflows: 27, each 12 m wide and 24 m high
  • Highest congestion target: 66 m above sea level
  • Normal congestion destination: 63 m above sea level
  • Water level on the valley side (underwater) 42 m above sea level
  • Difference in height of the water level upstream / downstream approx. 20 m
  • Total storage space: 1.58 billion m³
  • HWE design flow rate: 110,000 m³ / s
  • Nominal capacity: 2,715 GW
  • Number of turbines with 125 megawatts: 19 (14 of them in the main power plant)
  • Number of turbines with 170 megawatts: 2 (both in the power plant on the left)
  • Turbines used: Kaplan turbines
  • Standard energy capacity: 14.1 TWh. Increase due to improved flow regulation to 15.7 TWh
  • Resettled people: around 125,000
  • Build volume:
    • Removal of earth and rocks: 55.3 million m³
    • Filling of earth and rocks: 32.2 million m³
    • Concrete: 9.8 million m³
    • Structural steels: 623,300 tons

Information partly taken from:

After completion

The CGGC received an order to pass on the experience gained in planning, construction and operation to the China Three Gorges Project Corporation (CTGPC) founded in 1993. So that they can flow into the Three Gorges Dam project.

In 1996 the management of the power plant was transferred from the CGGC to the CTGPC. The CTGPC had been planning the Three Gorges Dam project since 1993 and would also operate it after construction was completed. This is intended to optimize operational processes and energy production and save costs.

Flood protection

The construction of the Gezhouba dam was to be used to generate the urgently needed electrical energy. There would also be improvements for shipping and flood protection. Flooding of the 1.5 million hectares of arable land downstream is to be prevented or reduced.

In the 20th century , flood disasters in China killed more than three million people . However, Gezhouba cannot prevent major events such as the flood disaster of 1931 . The available reservoir volume of 1.5 billion cubic meters is too small for this. The Yangtze River drains around 453 billion cubic meters of water into the sea every year.

Energy generation

At the foot of the dam, two power plants were built in which 21 Kaplan turbine units were installed. The standard energy capacity of the plant with its nominal output of 2.715 GW was 14.1 TWh. After the Three Gorges Dam went into operation, annual energy production increased thanks to the constant flow of water. In 2013 the power plant generated 15.7 TWh of electrical energy.

The hydroelectric power station can avoid the conversion of 10.2 million tons of coal per year into electricity.

Energy transfer

Transport of people and energy at the Gezhouba Dam

The generated electricity of 15.7 billion kWh (average annual output) is transmitted via high-voltage lines to the cities and provinces of Shanghai, Henan, Hunan and Wuhan.

navigability

Ships going uphill , in lock 2

The Yangtze River has been used by cargo and passenger ships for over 200 years. Some made it from the sea to the port of Yichang, 1,600 km away. After the Gezhouba Dam went into operation, the situation for shipping above Yichang hardly changed. As a result of the flooding of the reservoir, the water level only rose by around 20 m, which was compensated for again after around 28.5 kilometers with the low base gradient. Various fairways through narrow gorges and sections with shallow areas could only be navigated in "one-way traffic".

Only since the Three Gorges Dam went into operation in 2012 have cargo ships up to 10,000 gross register tonnes been able to safely enter the port of Chongqing, which is around 2,250 kilometers away from the sea .

It takes about 50 minutes to pass through Gezhouba Lock 2.

tourism

Because of Yichang's location at the eastern gateway to the Three Gorges, the city has become a tourist hub. Many passenger river trips start and end in Yichang.

Environmental impact

As the Yangtze River is known as a river that carries heavy debris and this has been scientifically proven, this fact was already taken into account in the planning. Otherwise, the plant operators would have to reckon with operational problems within a few years due to the silting up of the reservoir in front of the dam.

At the hydrological station near Yichang, an average annual sediment load of 523 million tons was determined. Given the high drainage of the Yangtze, this results in around 1.19 kilograms per cubic meter. A concept was developed in which the deposits behind the dam are flushed out annually. For this purpose, the level is lowered in March and April. In the rainy four months that followed, the river flows at a higher speed and flushes the sediments out of the reservoir through sediment sluices installed at a lower level.

Since the dam does not have a fish ladder , special spawning grounds for the Chinese sturgeon were created below the dam.

With the construction of the dam, the population of the sword sturgeon (Psephurus gladius) declined very quickly. The spawning grounds for this fish species were also further upstream. The sword sturgeon only occurred in the Yangtze. It has been an endangered species since 1996. For more than 10 years no more fish have been found in various searches. Except for 2003, two females but no fry were found. Therefore, the IUCN had listed the Psephurus gladius on its Red List of Endangered Species of October 24, 2009 as: "Critically endangered (possibly extinct)". On October 22, 2015, this species of fish was declared extinct by the IUCN.

Like the sword sturgeon, the Chinese river dolphin was only native to the Yangtze River. He is also considered to be extinct. The reasons given are restrictions on its habitat due to the dams, overfishing and water pollution

Forced relocation

The flooding affected a number of communities in the region that were under the administration of Yichang City. About 125,000 people had to be resettled. A third of the people being relocated were farmers whose farmland was flooded. It was more difficult to find new land for farmers than it was for silos and factories. Many farmers have had to give up their jobs and move to the city.

Operational problems

The annual monsoon rains in the summer months can lead to operational problems. If the snowmelt creates additional water, the risk of flooding increases. The Three Gorges Dam and the Gezhouba Dam reduced their production capacity by two thirds in July 2017.

See also

Movies

Web links

Commons : Gezhouba Dam  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e Robert Freer: The Three Gorges project on the Yangtze river in China , February 2001, p. 23. Retrieved January 26, 2019
  2. ↑ China Gezhouba Group Corporation: 1st International Symposium on Rockfill Dams , from 18. – 21. October 2009. Retrieved January 26, 2019
  3. ↑ Yangtze Cruise Tours: Gezhouba Dam . Retrieved January 26, 2019
  4. ↑ chinatourmap.com: Gezhouba Dam . Retrieved January 23, 2019
  5. ↑ Visit our China: Gezhou Dam . Retrieved January 26, 2019
  6. ↑ Travel China Guide: Gezhouba Water Conservancy Project , April 2, 2018. Accessed February 19, 2019
  7. ^ A b c Professor John F. Kennedy, Iowa Institute of Hydraulic Research, The University of Iowa (USA): Sediment, Flood-Control and Navigation Aspects of the Three Gorges Project, Yangtze River, China . Retrieved February 19, 2019
  8. ^ China Three Gorges Corporation: CTG History . Retrieved January 26, 2019
  9. ↑ a b Three Gorges and Yichang, YCNews.net: Gezhouba Dam , April 22, 2009. Retrieved January 26, 2019
  10. ↑ The Water Page: Yangtze River , May / June 2003. Retrieved February 19, 2019
  11. ↑ Christine Faustmann: Dreischluchtendamm on the Jangtsekiang - the largest hydroelectric power plant on earth . Matura thesis Geography & Economics, BG / BRG / BORG Hartberg 2002. Retrieved on January 26, 2019
  12. ↑ crienglisch.com: Three Gorges Dam and Gezhouba Dam , Gezhouba Water Conservancy Project (Gezhou Ba), February 6, 2006. Retrieved February 19, 2019
  13. ↑ a b Encyclopaedia Britannica: Yichang, China . Retrieved January 26, 2019
  14. ↑ The Christian Science Monitor: Chinese Paddlefish, Psephurus gladius, 2007 , October 22, 2015. Retrieved January 26, 2019
  15. ^ IUCN: Chinese Paddlefish , October 24, 2009. Retrieved March 8, 2019
  16. ^ The Christian Science Monitor: Yangtze River Dolphin, Baiji Dolphin (Lipotes vexillifer) , 2008. October 22, 2015. Retrieved March 6, 2019
  17. ↑ Süddeutsche Zeitung: In vain search for the last of its kind , report from May 19, 2019. Retrieved March 6, 2019
  18. ↑ Reuters World News: In drastic move, China's top hydropower plants slash capacity . Report dated July 4, 2017. Retrieved February 19, 2019