5. Region A: water surplus all year round (ATS > 200 mm) – Japan, eastern China & Taiwan, Malaysia, Borneo/Kalimantan, parts of Sumatra & Irian Jaya in Indonesia, Papua New Guinea, southeastern Philippines (eastern Mindanao). Region B1: water surplus with some months deficit (ATD < 200 mm) – west of Ghats Mountains & Assam in India, central & southern China, Java & Sulawesi in Indonesia, eastern, central & southwestern Philippines (eastern Luzon, Visayas, western Mindanao).

6. Region B2: water surplus with some months deficit (ATD > 200 mm) – east part of India, parts of Myanmar & Thailand along the Bay of Bengal, Lao PDR, Cambodia., Vietnam, northwestern Philippines (western Luzon). Region C1: water deficit with some months deficit (ATD < 200 mm) – Mongolia, part of Tibetan Plateau. Region C2: water deficit with some months deficit (ATD > 200 mm) – Deccan Plateau in India, leeward area of the southwest monsoon in Myanmar and Thailand, northern Australia.

7. The WMO (1967) developed the first set of envelope curves for maximum floods in the monsoon areas of the ECAFE (now ESCAP) region Modified Myer’s Formula: Q max = C A 0.5 Creager’s type Formula: Q max = C A ^ (b A -n ) where Q max = maximum recorded flood (m 3 /s); A = drainage area (km 2 ); ^ = exponential operator; C, b & n = empirical coefficients. Sub-region A (Burma, Ceylon, Pakistan, India): C = 206 (Modified Myer’s) C = 5.37, b = 1.44, n = 0.05 (Creager’s) Sub-region B (Cambodia, China, Indonesia, Laos, Malaysia, Thailand): C = 97 (Modified Myer’s) C = 0.35, b = 1.80, n = 0.05 (Creager’s) Sub-region C (Taiwan, Japan, Korea, Philippines, Vietnam) – typhoon subregion C = 364 (Modified Myer’s) C = 87, b = 1.00, n = 0.04 (Creager’s)

10. The Marikina River (A = 534.8 km 2 ) near Manila, draining to Manila Bay. Example of the annual daily rainfall hyetograph & streamflow hydrograph which are marked by the sharp peaks caused by the typhoon-intensified monsoon in 1990 – Also evident in the figure is the distinct dry season from January to May and the distinct wet season from June to December, … . consistent with the region B2 classification of western Luzon, Philippines (also called Type I climate in the Philippine Coronas classification system).

11. ADB data on number of deaths due to floods & droughts (1990-2001) versus Year-2000 population.

12. ADB data on economic losses due to floods & droughts (1990-2001) (million USD) versus Year-2000 population.

14. Countries in the UNESCO-IHP Catalogue of Rivers with analyzed annual maximum flood data (from Loebis, 2002) Countries Drainage Area (sq.km.) Australia (6 rivers) 25.9 to 129,500 China (9 rivers) 2,050 to 80,948 Indonesia (8 rivers) 948 to 12,804 Japan (9 rivers) 472 to 12,697 Korea (9 rivers) 612 to 11,104 Laos (6 rivers) 3,370 to 19,400 New Zealand (4 rivers) 556 to 6,350 Thailand (5 rivers) 4,609 to 38,862 For Q mean = C A b C b R 1.58 0.81 0.94 0.92 0.85 0.75 30.12 0.40 0.52 50.05 0.50 0.53 2.50 0.80 0.80 10.53 0.56 0.74 109.81 0.82 0.82 70.97 0.26 0.65 Countries For S Q = C A b C b R Australia (6 rivers) 1.21 0.83 0.93 China (9 rivers) 4.40 0.61 0.68 Indonesia (8 rivers) 205.38 -0.04 0.04 Japan (9 rivers) 89.26 0.36 0.53 Korea (9 rivers) 1.97 0.81 0.74 Laos (6 rivers) 13.05 0.46 0.72 New Zealand (4 rivers) 16.28 0.47 0.81 Thailand (5 rivers) 0.57 0.68 0.62

15. Conclusion: This paper has given a review and description of the characteristics of flooding in the Monsoon Asia region. A hydrological regionalization of the countries, based on a climatological water budget, is cited. Several maximum flood envelope curves are also reviewed. An example of a flood risk map for the Mekong River is provided. Likewise, an annual hydrograph of Marikina River near Manila is given as an illustration of the flooding effects of typhoon-intensified monsoons. The ADB data for the number of deaths and economic losses due to floods and droughts in the period 1990-2001 are plotted against the population in year 2000 of the various countries. Lastly, initial published results of regional flood frequency analysis, using some annual maximum flood data in Southeast Asia and the Pacific, are presented.

16. THANK YOU.