Author(s): Syed Rafiqul Alam Rumi
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Abstract: Flood in Bangladesh is a common phenomenon which occurs almost every year as a normal cycle of the season. The physical setting and location of Bangladesh is in such a place that it create an ideal situation for flooding every year. Within a large geologic setting Bangladesh constitute a small part. The country is located in a deltaic region formed by deposition of alluvia by three main rivers the Ganges the Brahmaputra and the Meghna (GBM) with their numerous tributaries and distributaries. The surface gradient is extremely low from northwards to the sea, so much so that the general idea of absolute flatness seems to be true. The average height of the alluvial plane is less than 10 metres above the sea level and the seaward slope is very gentle being less than 9 cm. per kilometre (Rashid, 1977). Over 60% of the country is flood prone. Moreover Bangladesh has a tropical monsoon climate characterized by heavy rain form one thousand to four thousand mm per annuam. At the same time, the Southwest monsoon wind raises the mean tide levels in the Bay of Bengal reduce water discharge capacity of the Meghna estuary (Elahi, 1992). As a result of the said topography and the very locational limitation, 30 to 35 percent of the country is flooded normally every year by over flowing main rivers during monsoon i. e. June-September (Ahmad, 2001). Therefore, normal flood can be said as a part of the overall hydrodynamic process active in the whole region (Khalequzzaman, 1994). These normal floods have some positive contribution for providing vital moisture and fertility to the soil through the alluvial silt deposition (UNEP, 2001). But severe floods which occurred occasionally are considered as disastrous like floods of 1974,1987,1988 and 1998 (Ali, 2001). Among these the 1998 flood was most disastrous in recent memory. It surpassed all previous records in terms of duration and inundation (Hussain, 1999). Occurring from July to mid September water at one point inundated 66 percent land surface of the country (Khan, 2000). The 1998 flood brought in untold suffering to millions of people, death, disease and hunger, damaged standing crops, fish including flora and fauna. Such was the impact of 1998 flood, possibly the country's worst ever. Extensive flooding of 1998 was linked with the flows of the three main river systems the Genges-Brahmaputra-Meghna (Nishat, 2000). Of the three first two passes along Northern Bangladesh.
Year: 2002