Case study: Opportunities and hazards in a river: Ganges/ Brahmaputra Delta in
Bangladesh
Bangladesh and the Ganges/Brahmaputra Rivers
 Bangladesh is an LEDC and is one of the poorest countries in the world with a
GNP of $2000 per head
 The drainage basin covers an area of over 1 million sq km and the combined
length of the two major rivers is nearly 4,000 km.
 Most of the land forms a delta from two main rivers – Ganges and Brahmaputra
(The Brahmaputra is a major tributary of the Ganges) and 25 per cent of
Bangladesh is less than 1 m above sea level
 The major floods happen from June through September.
 Most of the land in the delta is used for agriculture to grow rice and jute
 The population density is extremely high with more than 1,000 persons per
km².
Physical causes of the river flooding
 Most of the country consists of a large, flat flood plain and delta
 Snowmelt from the Himalayas takes place in late spring & summer
 Bangladesh experiences heavy monsoon rains. This means the rivers have their peak
discharge at the same time
 Tropical storms/ cyclones bring heavy rains and coastal flooding
Human causes of the river flooding
 Deforestation of the Himalayas – reducing interception rates which increases run off to
the rivers
 Urbanisation of the flood plain has increased amount of run off to the rivers.
Urbanisation has reduced the lag time and peak flow has greatly increased so flooding
is more frequent
 Climate change is blamed for increased snow melt in the Himalaya & increased number
of cyclone storms in the region
 Poorly maintained artificial levees collapse in times of high river discharge
Advantages of living in the delta region:
 The rivers are used for transportation of goods and encourage trade between the
capital city of Dhaka and the port city of Chittagong
 Factories are built along the riverside and the river water used in the industrial process
for cleaning and cooling machines.
 Water from the rivers can be used for irrigating their crops e.g. rice
and jute
 The flat floodplains of the delta are very fertile because of the
sediment deposited during the floods.
 The crop yields are high and provide a source of food and cash crops
for export e.g. rice and jute.
 Fish from the river provides an excellent source of protein
 The flooded area can also be used for shrimp farming
The impacts caused by flooding in the 2007 flood
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over 1,100 people killed
2 million acres of agricultural land was damaged and crops lost
10 million people were estimated to have been displaced
the main highway connecting Dhaka to the rest of the country was flooded isolating the
capital
many deaths caused by drowning, landslides and snakebites
2/3 of the land was flooded
100,000 people had caught dysentery / diarrhoea
Rice crops were devastated TWICE that year so farmers did not have time to recover
their losses and replant
Food insecurity caused some people to die from starvation
$150 million of aid was sought by Bangladesh
$300 million of crops were damaged in the initial floods
Economic Impacts
 2 million acres of
agricultural land was
damaged and crops
lost
Social Impacts
Environment Impacts
How is the risk of flooding being reduced?
 Bangladesh is an LEDC and therefore does not have enough money to implement large
flood control schemes. The Flood Action Plan was set up (1989) and is funded by the
World Bank.
 They built 350km of artificial levees costing $6 billion. Some of the levees are built of
mud but increasingly they are using concrete to reinforce the natural levees. These
increase the size of the cross section of the river channels so they can hold more
water
 They are in the process of building 7 large dams in Bangladesh to store excess
water
 Some river channels have been dredged (cleared of deposition) so that the channel is
deeper and can hold more water before flooding
 Flood satellite imaging systems have been developed to more accurately predict
flooding and allow more warnings to be given to the people. They are monitoring
hydrographs and rainfall patterns in the major drainage basins
 Some ways of reducing the risk of flooding include building 500 flood shelters on stilts
and setting up flood early-warning systems so that the people can evacuate to higher
ground.
 Emergency aid supplies were set up including organising stores of food, water and
tents and training emergency services in boat rescue
 The government of Bangladesh are in negotiation with the government of Nepal to try
to reduce the amount of deforestation in Nepal and to encourage the Nepalese to plant
trees. Bangladesh have helped fund afforestation projects in Nepal.
House on stilts, on low lying land