Construction Magazine March 2017 | Page 15

BUILDING THE THREE GORGES DAM
under 40 minutes . The structure is an impressive 113 metres high and can support vessels weighing up to 3,000 tonnes . It incorporates a helical gear system , where counter weights within the concrete walls help elevate the ships , in addition to over a thousand concrete blocks which are connected by cables .
Controversy Despite the need for the dam ’ s construction , concerns have been raised throughout the process surrounding the environmental aspects of the dam and the long term-complexities it has created .
Although it provides countless advantages , over 100,000 Chinese citizens had to be relocated as a result of the construction , and over five million tonnes of silt and sediment become trapped at the bottom of the reservoir every year . To counteract this threat to the dam and its functionality , engineers have inbuilt sluice gates which are situated inside the dam . Each gate weighs as much as a bus , which are supported through the use of hydraulic pistons . When the gates are opened , the trapped floodwater moves the sediment through the dam , minimising this risk .
Other areas of concern are the longterm consequences to aquatic life and food supply within China . The dam will disrupt the process of aeration in order for aquatic life and plants to thrive , creating a significant problem . In addition , there has been a need to relocate areas of food production , such as grains , which might not be able to be grown in less abundant soil . However , since its construction , the dam has stored approximately 39 billion cubic metres of water and supplied over 10 cubic kilometres of water to nearby cities and agricultural areas to support ongoing growth .
The Three Gorges Dam will be able to provide enough power for the growing Chinese economy , reducing the level of toxic emissions through the use of clean , cheap electricity . Coal consumption is reduced by approximately 30 percent per year , in addition to the reduction of carbon dioxide and sulphur dioxide . Despite the disadvantages to the dam ’ s construction , the long-term benefits should far outweigh the short-term complexities and will provide a sustainable solution to ensure the country ’ s prosperity .
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