Floods in Bangladesh

Bangladesh, being situated on the Brahmaputra River Delta (also known as the Ganges Delta) is a land of many rivers, and as a result is very prone to flooding. Due to being part of such a basin and being less than 5 meters above mean sea level, Bangladesh faces the cumulative effects of floods due to water flashing from nearby hills, the accumulation of the inflow of water from upstream catchments, and locally heavy rainfall enhanced by drainage congestion. Bangladesh faces this problem almost every year. Coastal flooding, combined with the bursting of river banks is common, and severely affects the landscape and society of Bangladesh. 80% of Bangladesh is floodplain,^[1] and it has an extensive sea coastline,^[2] rendering the nation very much at risk of periodic widespread damage. Whilst more permanent defenses, strengthened with reinforced concrete, are being built, many embankments are composed purely of soil and turf and made by local farmers. Flooding normally occurs during the monsoon season from June to September. The convectional rainfall of the monsoon is added to by relief rainfall caused by the Himalayas. Meltwater from the Himalayas is also a significant input.

In late summer 2002, heavy monsoon rains led to massive flooding in eastern India, Nepal, and Bangladesh, killing over 500 people and leaving millions homeless. This true-color image, acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra spacecraft begins on August 5, 2002, shows the extent of this flooding. In the upper right-hand corner of the image, the swollen Brahmaputra River runs east to west through the Indian state of Assam. Normally, the river and its tributaries would resemble a tangle of thin lines. Moving to the upper left-hand corner, flooding can be seen along the Ganges River in the state of Bihar, India.

Each year, on average, 31,000 square kilometres (12,000 sq mi) (around 21% of the country) is flooded. During severe floods the affected area may exceed two-thirds of the country, as was seen in 1998.^[3] Only about 20% of streamflow is generated by rainfall within Bangladesh. The other 80% flows in from catchment areas outside the country, overwhelmingly via three main rivers: the Ganges, the Brahmaputra-Jamuna and the Meghna.^[4] The floods have caused devastation in Bangladesh throughout history, especially in 1951, 1987, 1988 and 1998. The (2007 South Asian floods) also affected a large portion of Bangladesh.

^ H. Brammer (March 1990). "Floods in Bangladesh: Geographical Background to the 1987 and 1988 Floods". The Geographical Journal. 156 (1): 12–22. doi:10.2307/635431. JSTOR 635431.
^ Mohd Shamsul Alam (2012), "Sea Level", in Sirajul Islam; Ahmed A. Jamal (eds.), Banglapedia: National Encyclopedia of Bangladesh (Second ed.), Asiatic Society of Bangladesh
^ Dewan, A. M.; Nishigaki, Makoto; Komatsu, Mitsuru (March 2003). "Floods in Bangladesh: A Comparative Hydrological Investigation on Two Catastrophic Events" (PDF). Journal of the Faculty of Environmental Science and Technology, Okayama University. 8 (1): 53.
^ Chowdhury, Sifatul Quader; Hossain, Md Sazzad (2012). "Flood". In Islam, Sirajul; Jamal, Ahmed A. (eds.). Banglapedia: National Encyclopedia of Bangladesh (Second ed.). Asiatic Society of Bangladesh.

[1] H. Brammer (March 1990). "Floods in Bangladesh: Geographical Background to the 1987 and 1988 Floods". The Geographical Journal. 156 (1): 12–22. doi:10.2307/635431. JSTOR 635431.

[Banglapedia-2] Mohd Shamsul Alam (2012), "Sea Level", in Sirajul Islam; Ahmed A. Jamal (eds.), Banglapedia: National Encyclopedia of Bangladesh (Second ed.), Asiatic Society of Bangladesh

[3] Dewan, A. M.; Nishigaki, Makoto; Komatsu, Mitsuru (March 2003). "Floods in Bangladesh: A Comparative Hydrological Investigation on Two Catastrophic Events" (PDF). Journal of the Faculty of Environmental Science and Technology, Okayama University. 8 (1): 53.

[4] Chowdhury, Sifatul Quader; Hossain, Md Sazzad (2012). "Flood". In Islam, Sirajul; Jamal, Ahmed A. (eds.). Banglapedia: National Encyclopedia of Bangladesh (Second ed.). Asiatic Society of Bangladesh.

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