Rivers, Floods and Management - Bangladesh Case Study

Question 1

Location

Answer 1

South-Central Asia

Question 2

Frequency of major floods

Answer 2

Every 8 years

Question 3

3 major rivers

Answer 3

Meghna
Brahmaputra
Ganges

Question 4

Capital of Bangladesh

Answer 4

Dhaka

Question 5

Population of Bangladesh’s capital

Answer 5

Dhaka 1 million

Question 6

How much rainfall fell in Bangladesh and when? This was the worst rain for how many years?

Answer 6

350mm in 24 hours
13th September 2004.
Worst rain for 50 years.

Question 7

How much of Bangladesh is how far above sea level? Why?

Answer 7

20% less than 1 metre above sea level.

Because it is built on a floodplain on delta land.

Question 8

Summary: 5 physical causes of Bangladesh flood

Answer 8

• Heavy rainfall
• Monsoon climate
• Low lying
• Himalayas
• 3 major rivers

Question 9

What system was put in place for farming? Which river? Effects?

Answer 9

Irrigation system to divert the Ganges.

Reduced speed of flow in channels = more deposition inland, less on low lying delta = didn’t build up

Question 10

Name 2 places where urban growth occurred

Answer 10

Nepal and Tibet

Question 11

Summary: 4 human causes of flood

Answer 11

• Irrigation diverted Ganges
• Urbanisation
• Deforestation of Himalayas
• Global warming

Question 12

Deaths

Answer 12

800

Question 13

How much of the country was flooded?

Answer 13

38%

Question 14

How much of Dhaka was under water and in which month?

Answer 14

40% under water in July

Question 15

How many bridges destroyed?

Answer 15

900

Question 16

How much road damaged?

Answer 16

15,000 km

Question 17

How much farmland destroyed?

Answer 17

800,000 ha

Question 18

How many people suffered from diarrhoea in Dhaka?

Answer 18

100,000

Question 19

Cost of total damage?

Answer 19

$7 billion

Question 20

2 other long term impacts

Answer 20

Rice crops devastated = food shortages

Jute and sugar cash crops rotted = money shortages

Question 21

How much aid did the UK give?

Answer 21

£21 million

Question 22

How much aid did the UN appeal for? How much did they actually get?

Answer 22

Appealed for $74 million.

Only got 20% by September

Question 23

What charity gave Bangladesh short term aid?

Answer 23

Water aid - water purification tablets

Question 24

2 other short term responses

Answer 24

• NGOs: rice, clothing, medicine, blankets

- Farmers given free seed

Question 25

9 long term responses

Answer 25

- Flood action plan formed - Early warning system - sluice gates - 2 ha of raised land for flood shelter - Coastal homes on stilts - homes raised by 2m on earth banks - Embankments strengthened - Self help schemes: rebuilt homes & communities - Additional financial aid granted

Question 26

By how much were homes raised on earth banks?

Answer 26

2m

Question 27

How much raised land was created for flood shelter?

Answer 27

2 ha

Question 28

Date

Answer 28

2004 July---> September

Question 29

What economic factor limits Bangladesh's ability to manage floods?

Answer 29

GDP per capita = $700 and tax revenue limited = rely on foreign aid and NGOs

Question 30

Why did heavy rainfall lead to flooding?

Answer 30

Groundwater stores filled = water table reached surface = surface runoff

Question 31

When is the wet season?

Answer 31

May to September

Question 32

What causes rain to coastal regions? How did this lead to floods?

Answer 32

Low pressure and winds fro southeast = heavy rain | Meghan reached peak level in July

Question 33

What brings intense precipitation and storm surges?

Answer 33

Cyclones from Bay of Bengal

Question 34

What area of Bangladesh is easily washed away by floodwater and why?

Answer 34

Densely populated island - Chars | Made up of mud deposits = unstable

Question 35

How did Himalayas lead to flooding? 3 ways

Answer 35

1. Snow and glacial melt increase discharge of Ganges and Brahmaputra 2. Tectonic uplift = rivers have more GPE = more erosion = sediment deposited downstream which chokes channels 3. Relief rainfall - high slopes = faster and more runoff

Question 36

Which glacier in himalayas contributed to flooding and how?

Answer 36

Gangotri Glacier in Indian Himalayas feeds ganges. Melts at 25m per year.

Question 37

what type of causes have become more important in recent decades?

Answer 37

Human causes of flooding

Question 38

Where did deforestation occur and why?

Answer 38

In Himalayas due to pop pressure in Nepal and Tibet - need more grazing land and wood for fuel

Question 39

How did deforestation contribute to flooding?

Answer 39

Less interception and evapotranspiration = more runoff | Soil erosion = river bed aggradation = reduced capacity

Question 40

How did urbanisation contribute to flooding?

Answer 40

Impermeable surfaces = more runoff and less infiltration = discharge increased, lag time decreased. Increased magnitude and frequency of flooding.

Question 41

How did global warming contribute to flooding?

Answer 41

- More extreme weather = increased quantity and intensity of monsoon rain - Higher temp = more snow melt

Question 42

By how much is rainfall estimated to increase due to global warming and by when?

Answer 42

10-15% increase by 2030

Question 43

How much rice was destroyed?

Answer 43

2 million tonnes

Question 44

Who lost their livelihoods?

Answer 44

Subsistence farmers

Question 45

What infrastructure was damaged?

Answer 45

Railways, roads, embankments, irrigation system

Question 46

What groups of people were most affected?

Answer 46

Poor farmers, landless labourers and slum dwellers

Question 47

How many people homeless?

Answer 47

36 million (25% population)

Question 48

How much untreated sewage escaped into water each day?

Answer 48

500,000 cubic meters

Question 49

5 environmental impacts of flooding

Answer 49

1. Land flooded 2. River bank erosion on embankments near main channels 3. Soil erosion 4. Waterlogged urban areas 5. Water Contamination

Question 50

Describe early warning system put in place

Answer 50

- Satellite monitoring linked to local radio stations to send warnings - warnings from loudspeakers in Mosques

Question 51

Who and for how long was financial aid granted?

Answer 51

5 year period | - World bank loan to paid for infrastructure repairs, water resources management and education

Question 52

What dates did Bangladesh have catastrophic flooding again?

Answer 52

2007 and 2010

Question 53

Why is Bangladesh under greater threat?

Answer 53

Sea level rise and more storm surges | Climate change made cyclones more powerful = higher storm surges

Question 54

How much is temp supposed to rise Bay of Bengal?

Answer 54

2- 4 degrees next 40 years

Question 55

What rise in sea level would be catastrophic and why?

Answer 55

50-100 cm rise = 20% country flooded = 15 M refugees