Describe the features and characteristics of the Three Gorges Dam. Explain the impacts that dams and reservoirs have on river hydrology. Examine the role of dams as multi-purpose schemes.

http://www. dailymotion http://www.dailymotion.com/video/x28edpc_sacred-rivers-with-simon-reeve-3-the-yangtze_travel Watch from 30:34 to 36:40 Describe the location of the Three Gorges Dam. Explain why it was built. Give 5 relevant facts about its operations.

How do dams affect river hydrology: CHANGES TO HYDROLOGY UPSTREAM OF DAMS CHANGES TO HYDROLOGY DOWNSTREAM OF DAMS Increased evaporation rates because reservoirs have a larger surface area than rivers. An increase in the amount of surface store (reservoirs are an artificial store). A reduction in the velocity of the river upstream. The river was effectively flowing into a stationary store of water. Increased sedimentation can lower the depth of the river and the reservoir. Again this will reduce velocity and may also reduce storage capacity. River discharge will decrease because water is being held behind the dam. A rivers' discharge may become more regular (less extremes) because the flow of water is regulated. Clear water erosion may cause the bed of the river to lower. There is no sediment (load) to be deposited to replace erosion. The amount of load transported by the river will reduce because less sediment is reaching downstream. The salinity of the water and the ground may increase. The temperature of the water may reduce, as water released from reservoirs is often colder (reservoir deeper than river). The water may also be less oxygenated than natural free flowing water. With smaller discharge the velocity of the river may decrease, because the level of the river is further below bankfull discharge so the hydraulic radius is smaller. The amount of depositional landforms may reduce e.g. alluvial fans, levees, deltas and slip off slopes. Use the following resources to apply these ideas specifically to the events that have occurred at the Three Gorges Dam. Remember that you are specifically looking for evidence of these listed changes.

Impacts upon Yangtze hydrology: http://www.nature.com/news/2011/012345/full/news.2011.315.html http://peakwater.org/tag/three-gorges-dam/ http://esseacourses.strategies.org/module.php?module_id=51

Examine the success of the dam as a multi-purpose scheme: What is a multi-purpose scheme? Can you give any other named examples? What are the different ‘purposes’ of the Three Gorges Dam? Create a table to outline the advantages and disadvantages of the dam. You may wish to think about its implications in the following areas: Positives: agriculture, irrigation, energy, navigation, fishing, flood control, employment. Negatives: culture, religion, settlement, hydrology (erosion and deposition), pollution, river ecology, economic cost, geological instability. https://www.youtube.com/watch?v=3z9K82ZVdMA