Causes and Impacts of flooding in an LEDC- Bangladesh 2007
Causes and Impacts of flooding in an LEDC- Bangladesh 2007
Introduction
Bangladesh is located in the south of Asia. It is bordered by India to its north, west and east and by Burma to its south east. The Bay of Bengal is south of Bangladesh and the country lies on the fertile Bengal Delta. The map below shows the location of Bangladesh and shows the two rivers; the Brahmaputra and the river Ganges running through Bangladesh. In July and august 2007 both Bangladesh and India suffered from severe flooding.
Flooding in Bangladesh is a frequent event, with it often inundating between 20 and 30% of the country and causing mass devastation and deaths. It often happens in the late summer as Bangladesh has a monsoon climate, with 80% of the rain falling within 4 months. 90% of Bangladesh is less than 10m above sea level so it is very low lying. Another factor is melting snow and ice from the Himalayas which led to the rivers discharge rising, it had a particular effect on the Brahmaputra river.
Causes
Physical- The monsoon came very quickly and came after a particularly dry and early summer, which resulted in the ground being baked and therefore being less permeable. Also the rainfall was very heavy. Assam had a record of 169.5 mm in 24 hours on the 22nd of July and 900mm in total for July. This long duration of precipitation left the soil completely saturated and as the rate of precipitation quickly exceeded the infiltration capacity. The surface runoff increased dramatically and in turn as did the river’s discharge. Another aspect which lead to the flooding was that the peak discharge of the river Ganges and the Brahmaputra coincided so this increased the river discharge downstream. These physical aspects were the main cause of the flooding but human activities did also had an impact.
Human-deforestation in the Nepal and the Himalayas meant that a lot less rainfall was intercepted and taken up by roots so the discharge was increased. Also the growth of urban area
Introduction
Bangladesh is located in the south of Asia. It is bordered by India to its north, west and east and by Burma to its south east. The Bay of Bengal is south of Bangladesh and the country lies on the fertile Bengal Delta. The map below shows the location of Bangladesh and shows the two rivers; the Brahmaputra and the river Ganges running through Bangladesh. In July and august 2007 both Bangladesh and India suffered from severe flooding.
Flooding in Bangladesh is a frequent event, with it often inundating between 20 and 30% of the country and causing mass devastation and deaths. It often happens in the late summer as Bangladesh has a monsoon climate, with 80% of the rain falling within 4 months. 90% of Bangladesh is less than 10m above sea level so it is very low lying. Another factor is melting snow and ice from the Himalayas which led to the rivers discharge rising, it had a particular effect on the Brahmaputra river.
Causes
Physical- The monsoon came very quickly and came after a particularly dry and early summer, which resulted in the ground being baked and therefore being less permeable. Also the rainfall was very heavy. Assam had a record of 169.5 mm in 24 hours on the 22nd of July and 900mm in total for July. This long duration of precipitation left the soil completely saturated and as the rate of precipitation quickly exceeded the infiltration capacity. The surface runoff increased dramatically and in turn as did the river’s discharge. Another aspect which lead to the flooding was that the peak discharge of the river Ganges and the Brahmaputra coincided so this increased the river discharge downstream. These physical aspects were the main cause of the flooding but human activities did also had an impact.
Human-deforestation in the Nepal and the Himalayas meant that a lot less rainfall was intercepted and taken up by roots so the discharge was increased. Also the growth of urban area