Advantages of Three Gorges Dam
Operated in 1993 and completed in 2009, Three Gorges Dam is designed to serve three main purposes: flood control, hydroelectric power production and navigation improvement, which are also the great advantages of this project.
Controlling flood is one of the most significant functions of the Three Gorges Dam, and flooding used to be a major problem for the seasonal Yangtze River. With millions of people living downstream of the dam and many large and important cities like Wuhan, Nanjing and Shanghai situated adjacent to Yangtze River, flooding control has been one of the most issues for China.
The flood storage capacity of Three Gorges Dam Reservoir is 22 Cubic Meters, and this capacity can reduce the frequency of major downstream flooding from once every ten years to once every 100 years.
As the world’s largest power station of 22,500 MW, Three Gorges Dam project has installed 32 main turbines with two smaller generators to power the plant itself. From 2003 to 2014, the annual power generating is increasing and there was 83.7 terawatthours (TWh) in 2013 and 98.8 TWh in 2014. This electric generating capacity has largely supported the whole nation’s electricity usage.
Cruise Ships Navigation
The installment of ship locks and equipped with a ship lift on Dam, the Yangtze Three Gorges cruise ships heading towards much safer.
Besides, the Three Gorges Dam reservoir goes as far as to the southwest metropolis Chongqing, therefore it improves 660 kilometers waterway, and largely enable 10000 – tonnage fleets to navigate between Shanghai and Chongqing. The annual one – way navigation capacity of the Yangtze at the dam will be upgraded from ten million tons to fifty million tons.
Disadvantages of Three Gorges Dam
Comparing with the advantage of the dam, people focus more on the disadvantages of Three Gorges Dam, which is existed indeed and can’t be omitted. Among those bad impacts, Water Pollution, Migration Problem and Environment Problem to surrounding ecology and sceneries are the most disadvantages.
Along with the river flowing, there is a large number of land experiencing erosion, which leads to tons of sands and pebbles into the Yangtze River and stay at the upstream and makes great water pollution about Yangtze River.
Chinese officials estimate that the reservoir will partially or completely inundate 2 cities, 11 counties, 140 towns, 326 townships, and 1351 villages. About 23800 hectares, more than 1.1 million people will have to be resettled.
In order to build the dam, the surrounding landscape has been changed largely, which has caused some problems related to climate deteriorated, plants and wildlife disappeared, historical relics submerged, etc.
The Three Gorges Dam project construction has brought different advantages and disadvantages and local authorities are trying their best to reduce the bad impacts. Tourists can’t have chance to appreciate those submerged cultural relics but at the same time some new scenic spots with authentic sceneries are waiting for you to explore.
In the IGCSE Geography Specification, you're meant to know a case study for a dam or reservoir project, and I learnt this, so...:
Case Study of a Dam or Reservoir Project: The Three Gorges Dam, Yangtze River, China (multi-purpose scheme)
Yangtze River: Intro Facts
· Source=Himalayas, flows into the East China Sea at Shanghai
· 3rd longest river in the world
· Floods regularly, unpredictable, prone to severe flooding (every 10 years on average)
· Last great flood-1998, an area the size of New Zealand was flooded
· US$30 billion worth of damage
· In the 20th century, over 300,000 people have been killed by the Yangtze floods
The Three Gorges Dam: A multi-purpose scheme
Main purpose: to prevent flooding downstream
· Generates HEP (hydro-electric power)
· Provides water to urban areas and to agriculture (irrigation)
· Will improve river transport upstream
Cost-Benefit Analysis of the Three Gorges Dam
Benefits/Advantages/Positive Effects (in order of importance according to me)
1. Control flooding downstream of the dam.
2. Provides water to urban areas and for agriculture-irrigation. (The reservoir can store up to 5 trillion gallons of water.
3. The HEP generated will provide 15% of China’s electricity demand.
a. This will decrease China’s dependency on coal and therefore reduce greenhouse gas emission.
4. Thousands of construction jobs were created during the building of the dam.
5. China will be able to bring 10,000 ton ocean going vessels all the way inland, 2000km up to the city of Chongqing.
6. The dam will become a tourist attraction and will attract a lot of people to the area. Many tertiary sector/service jobs will be created.
7. The electricity generated will help the economic development of cities such as Chongqing, population=3 million.
Costs/Disadvantages/Negative Effects (in order of importance according to me)
1. Several large towns upstream, such as Fuling (population=80,000) and Wanxian (population=140,000) will be flooded.
a. Ancient temples, burial grounds and other historic sites will be lost beneath the reservoir too.
2. Over 1.3 million people will have to be relocated.
3. Much of the land used for resettlement is over 800m above sea level, where the climate is colder and the soil can barely support farming.
4. The pressure created by the huge weight of the water in the reservoir behind the dam could trigger earthquakes. (But it is engineered to withstand an earthquake of 7.0 on the Richter scale.)
5. The untreated human and industrial waste will not be washed away downstream, but will stay and pollute the river instead.
6. Areas downstream will be deprived of fertile sediment.
7. It will divert money from other developments. It is currently one of the most expensive projects in the world, costing more than $26 billion, over their budget.