Sunday, 25 May 2008
here's more information that we can use for our project!
i think using it for the introduction would be good(:
What are water dams?A water dam is a barrier that divides waters.
Dams generally serve the primary purpose of retaining water, while other structures such as floodgates, levees, and dikes are used to prevent water flow into specific land regions.
The tallest dam in the world is the 300 meter high Nurek Dam in Tajikistan.
Three Gorges DamThe three Gorges dam, therefore, is the China Yangtze Three Gorges Project (TGP) as one of the biggest hydropower-complex project in the world.
It ranks as the key project for improvement and development of Yangtze River.
The dam is located in the areas of Xilingxia gorge, one of the three gorges of the river, which will control a drainage area of 1 million km 2 , with an average annual runoff of 451 billion m3 .
The open valley at the dam site, with hard and complete granite as the bedrock, has provided the favorable topographical and geological conditions for dam construction.
As everybody here knows, energy cannot be created or destroyed, but it can be converted into other forms of energy.
Purpose of the dams in chinaThe Three Gorges Dam was built for
Flood Control.
Floodgates are adjustable gates used to control water flow in reservoir, river, stream, or levee systems.
They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and canals, or they may be designed to stop water flow entirely as part of a levee or storm surge system.
In the case of flood bypass systems, floodgates sometimes are also used to lower the water levels in a main river or canal channels by allowing more water to flow into a flood bypass or detention basin when the main river or canal is approaching a flood stage.
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.
The second reason is for
Power Generation.The river water will generate electricity in the hydropower stations.
The profits are considerable. With the Three Gorges Hydropower Plant (TGHP) containing 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, the anticipated annual electricity generation is 84.6 billion kilowatt hours.
It will be the number one in the world and will play an important role in the development of the economy and reduction of environmental pollution.
This is linked to
Tourism as the Three Gorges Dam Project will be the largest water conservancy in the world combined with the world-renowned natural beauty.
It will become the "hottest" tourist and press attraction in recent years.
Lastly, the 600km long waterway from Yichang to Chongqing will aid in
Navigation.
This waterway will be improved, making it possible for 10,000 tons of shipping to sail directly upstream to Chongqing.
The river transport will be improved from 10 million to 50 million tons per year and the costs reduced by 35-37 percent.
After the adjustment to the reservoir, navigation conditions both upstream and downstream on the Yangtze River will have been greatly improved in those seasons when water levels have been low.
there(:
;2:26:00 am
