Study on Recent Floods and Droughts in Southeast Asia and the Pacific

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The floods and droughts in the 1990's in Southeast Asia and the Pacific were investigated and analyzed towards the practicable disaster prevention management in the region. The study was conducted in collaboration with many researchers in Southeast Asian and the Pacific countries through the Asian Pacific FRIEND (Flow Regimes from International Experimental and Network Data) of UNESCO IHP (International Hydrological Program). The following are the list of selected investigation outcomes. The details are in this report as well as in the Proceedings of Asian Pacific FRIEND and GAME Joint Workshop on ENSO, Floods and Droughts in the 1990's in Southeast Asia and the Pacific in the 1990's held in Hanoi, on 23-25 March 1999 (IHP Regional Steering Committee for Southeast Asia and the Pacific and Vietnamese IHP National Committee (eds)).Floods in the 1990's occurred not only in the flood prone warm humid regions but also elsewhere like US, Canada, Europe, Korean Peninsula and even arid and sem … More i-arid regions such as Tunisia, Iran, Egypt and Yemen. The frequency of floods and droughts seems increasing in the recent decades.The El-Nino of 199 1-94 and 97-98 gave great impacts on hydrology and water resources, mainly as severe droughts, to Southeast Asia and the Pacific, especially in the areas of the lower latitudes between 20N and 20S.The impact of 97 EI-Nino was among others especially devastating.The El-Nino influences different regions in different way. In Vietnam, Laos, Cambodia, Thailand, Myanmar, Malaysia, Australia and New Zealand, it brings direct impacts on precipitation and river runoff. On the other hand, it is indirect in China, R.Korea, DPR Korea and Japan. As a result, there is a strong interest in countries of the former group seeking for the possibility of predicting rainfall and river discharge from SOI's and SST's.The main factors affecting the 1998 Great China floods may be such as concentrated heavy rainfalls, reduced basin retardation capacity such as in Lake Dong Ting and due to deforestation, extension of continuous levee system, decrease of dike breakage sites and decrease of channel capacity due to sedimentation and human dwelling.The 1997 Indonesian forest fires and consequences were not only due to very severe droughts but also due to various human factors.Death tolls by disasters are proportional to the poverty of the national economy. Poor countries are more tragic to disasters than the rich. On the other hand, economic losses may not necessarily be reduced regardless of flood control investments. Less