Development in Flood Zone

The world population has more than doubled in last 50 years (from 2.52 billion in 1950 to 6 billion in 2000). Moreover the United Nations (1999) estimate that 97% of growth is taking place in less developed countries, with Africa as a fast growing Area. Cities such as Bombay, Calcutta, Karachi, Jakarta, Nairobi, Manila, Lagos and Cairo are examples of rapid human concentration. This makes the current planning strategies insufficient and ineffective (if they even exist). Consequently, slums and squatters and informal settlements in those cities are the expression of a marginalization of a big and growing range of city dwellers (Sietchiping 2000). It is undeniable that landuse is continuously changing. The speed of urbanization, of forest clearance and of agricultural under drainage and ploughing up of natural grassland have increased flood potential (Ward 1978). Usually informal settlements are located on vulnerable and unbuilt areas such as deep valleys (Nairobi), river banks (Bombay), abandoned waste dumps (Manila) or dangerous slopes (Yaounde). They are known as catastrophe prone areas (floods, landslides and health hazard). It has originated from difficult problems of housing, immigration rates, politics, physical planning, landlessness, and employment in urban areas (Sietchiping 2000). Many build their homes and grow their food on river flood plains intowns and cities (Douglas 2008). Inundation along some of the low-lying floodplains adjacent to major rivers can be both widespread and long in duration (Zillman 1999). In the case of the Ganges–Brahmaputra–Megna river system in Bangladesh, 110 million people are relatively unprotected on the floodplain of southern Asia’s most flood-prone river system (Smith 1996 pg 258). But risks are also great for settlements in small river basins subject to sudden flash floods and along low-lying shorelines where storm surges associated with cyclones can produce sea flooding of several meters in depth (Zillman 1999).

Davis and Hall (1999) argue that poverty can drive people toward settling and working in precarious locations such as unstable riverbanks in farming areas. Of Asia’s great population, 89% of the gainfully employed population of Thailand, 73% of that of Korea, 70% of that of Burma, 69% of that of Philippines and 67% of that of India is engaged in agricultural production (Bureau of Flood Control 1950). The alluvium of river valleys and river deltas provide the most suitable area for agriculture. The flat topography of these areas lends itself admirably to farming (Bureau of Flood Control 1950). In