Rivers Of Bangladesh (2)

Question 0

Drainage basin and water shed

Answer 0

Covers most of Bangladesh, parts of India, Nepal and China too
Watershed is made up of Himalayas and Tibetan plateau

Question 1

The three rivers of Bangladesh

Answer 1

Meghna
Ganges
Brahmaputra

Question 2

Brahmaputra

Answer 2

Covers 1000 kilometres (can’t cut through resistant rock of Himalayas)
Flood plain covers 50% of Bangladesh
Deposits sediment in its upper course and it erodes there too

Question 3

Reasons why the river floods

Answer 3

Monsoon and snow melt
Deforestation
Overflow
Channel straightening and canalisation

Question 4

Monsoon and snowmelt

Answer 4

Huge tidal waves and storm conditions
Waves reach 7m high and have very destructive effects
People are forced to live in flood plains, particularly the poor in islands in the delta

Question 5

Deforestation

Answer 5

Lack of trees exposes soil to rain splash

Loosens particles in soil and produces surface runoff

Question 6

Overflow

Answer 6

Increase in soil erosion increases amount of sediment deposited
Rivers in Bangladesh carry 1600 tonnes of slit per kilometres per second

Question 7

Channel straightening / canalisation

Answer 7

Increases rivers speed and more water is carried faster downstream
However can be stopped by building levees that can prevent the water draining away quickly

Question 8

Benefits to flooding

Answer 8

Farmers don’t mind them as although it brings disaster, it also provides a free fertiliser
Washes out salt from crops
Flushes out disease

Question 9

Disastrous effects on flooding

Answer 9

Death of both people and animals
Destruction of homes and possibly whole islands of the delta
Death of fish populations ~ means poor diets as most people have 80% of their protein from fish

Question 10

Are flood control schemes the answer

Answer 10

Sometimes the river floods despite having millions of dollars being spent on preventing this disaster

Question 11

What are the schemes used

Answer 11

River straightening and levees
Dams
Tidal barrage across Bay of Bengal
Urban flood protection levees

Question 12

River straightening and levees

Answer 12

Rise banks
Makes water difficult to drain away onto flood plain
Straightening can increase rivers power and carries floods away faster

Question 13

Dams

Answer 13

Holds water back
May alter rivers flow
Slit gets tapped behind dam rather than in the flood plain

Question 14

Tidal barrage across Bay of Bengal

Answer 14

Expensive
Protects land of the poorest people
Prevents water draining away freely
Reduces salt in the delta, making crops more reliable
But building up of chemicals and pesticides may occur

Question 15

Urban flood protection levees

Answer 15

Protects the richer people
Reduces problems related to breakages in sewage
Reduces spread of disease

Question 16

Other methods of protecting people other than using flood control

Answer 16

Killas
Embankments
Satellite technology or warning systems
Urban flood protection

Question 17

Killas

Answer 17

House up to 1000 people
Concrete shelters for people and animals on stilts
Can shelter there for days
Cheap, easy to build, can help both poor and rich areas

Question 18

Embankments

Answer 18

Strengthen river banks
Structures up to 7m high
Expensive, restricted access to river for fishermen

Question 19

Satellite technology for warning systems

Answer 19

Increasing accuracy to predict when storms and floods are most likely to occur
Improves IT skills

Question 20

Urban flood protection

Answer 20

Targets most populated areas
Benefits richer people
Not necessarily protects from risks of pollution