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Coping with the monsoon |
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University of Padua IMAGE Department |
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Southern Asia and Indo-China are in the northern tropics and have dry and wet climates. The monsoon wind brings rain to some regions while others are left relatively dry. The lenght of the summer monsoon season varies fron year to year, but the warm and humid air produces precipitation from May to November. The winter monsoon is characterized by dry and cold winds which , after a long journey over sea, expose coastal areas such as south-eastern India, north-eastern Sri Lanka and the eastern part of the Philippines to heavy rain. These same areas are relatively dry during the summer monsoon (Visvanathan C. et al., 2003). The rainfall characteristics for local climates must be considered when designing (Hogland W. et al., 2005): • Top and botton liners • The leachate drainage and treatment system • Gas collection systems • The final cover. Protection against erosion should be incorporated and the stormwater run-off collected and conveyed out of the area without coming into contact with the waste. Stormwater from sorting areas, the weighbridge area (if it exists) and workshop area for vehicle repair should be collected and treated. The estreme monsoon rainfall can create a high amount of leachate and stormwater run-off over a short period, while the very high evaporation of the subsequent dry season is likely to have the opposite effect. The dry regions are characterized by conditions caused by arid climates. Here, leachate generation can cease. In both climate conditions, it is essential to design the bottom liner and other elements of the leachate control system accordingly. |