Flooding in Bangladesh Key idea: The effects of and responses to floods vary between areas of contrasting levels of wealth
To study a case study of flooding from a poorer part of the world - Bangladesh
To know the effects of flooding
To know the responses to the frequent flooding event
Starter activity…. Sketch the map below and label the countries : China India Nepal Bangladesh Pakistan Bhutan Burma (Myanmar)
Physical causes of flooding Almost all of Bangladesh’s rivers have their source outside the country.
Bangladesh has three mighty rivers, the Ganges, the Jamuna and the Meghna
Freshwater floods occur when a watershed receives so much water that it cannot drain into the soil quickly enough to take the water away..
Most floods follow heavy rain or melting snow, frozen ground and already high river levels.
The floods in Bangladesh begin through a combination of heavy monsoon rains flooding the rivers and abnormally high tides in the Bay of Bengal preventing floodwater from running off the land and into the sea.
The deltas of the Ganges and Brahmaputra rivers in South Asia flood on a seasonal basis. The flooding keeps the soil fertile because the rivers deposit silt which forms fertile soil each year. Partly because of the flooding, it is one of the most densely populated areas of the world (900 people per km 2 ). Millions of people in Nepal, Northern India and Bangladesh depend on the rivers and fertile soils for their livelihoods. Tear Fund UK
Flooding in Bangladesh Where does the flooding occur? Identify specific regions that are worst hit.
80% of Bangladesh is located on the delta. The low level of the delta land means that large areas are prone to flooding. 75% of Bangladesh is at or below just 10 metres in height.
Total rainfall within the Brahmaputra, Ganges – Meghna catchment is very high and very seasonal. 75% of annual rainfall occurs in the monsoon between June and September. Annual rainfall total in Dhaka is almost 2000mm Tropical cyclones from Bay of Bengal bring heavy rain and storm waves in late summer
Bangladesh also suffers regularly from substantial flooding melting snows from the Himalayas. Source: World Infozone.com
Human factors that cause flooding
Deforestation may be partly to blame, stripping the land bare of the vital top soil which slows and drains water. This causes soil erosion which reduces the ability of the land to absorb water.
Irrigation for farming is a factor, because this causes river channels to silt up, reducing their capacity to hold flood waters. According to some experts, irrigation interferes with river drainage into the sea.
Climate experts also believe global warming is partly to blame, by increasing monsoon rainfall and speeding up the melting of Himalayan snows.
In built-up areas with a lot of concrete roads and houses, there are fewer places for water to go and less soil for water to drain into. Planners in cities prone to flooding have to develop ways of channelling water to cope with potential floods.
Flooding in Bangladesh
Bangladesh - Fact File
is one of the world's most densely populated countries!
has a population of 125m inhabitants
is one of the poorest countries in the world with a GNP of $200 per head
has three of the world's most powerful rivers passing through its country - The Ganges, the Meghna & the Brahmaputra
contains virtually no raw materials or rock
experiences floods and tropical storms every year
The Physical Causes of the Floods
Most of the country consists of a huge flood plain and delta . 70% of the total area is less than 1 metre above sea level
10% of the land area is made up of Lakes and Rivers
Snowmelt from the Himalayas takes place in late spring & summer
Bangladesh experiences heavy monsoon rains , especially over the highlands
Tropical storms (= cyclones) bring heavy rains and coastal flooding
The main cause was the above average & long period of heavy rain which caused all 3 rivers to have their peak flow at the same time!!!
The Human Causes of the Floods
Deforestation in Nepal and the Himalayas increases run off and adds to deposition and flooding downstream
Urbanisation of the flood plain has increased magnitude & frequency of floods
the building of dams in India has increased the problem of sedimentation in Bangladesh
Global warming is blamed for sea level rise, increased snow melt & increased rainfall in the region
Poorly maintained embankments (levees) leak & collapse in times of high discharge
The Effects of the 1998 Floods
Over 57% of the land area was flooded
Over 1300 people were killed
7 million homes were destroyed
25 million people were made homeless
There was a serious shortage of drinking water & dry food
Diseases spread such as bronchitis and cholera/diarrhoea
As the waters receded - it left fields of rotting crops, wrecked roads and bridges and destroyed villages
2 million tonnes of rice was destroyed
1/2 million cattle and poultry were lost
Overall the floods cost the country almost $1 billion
2004 Floods in Bangladesh floods occurred July to Sept July 2004 - 40% Dhaka was under water 60% of country was flooded 600 reporte deaths 20 million homeless 100,000 in Dhaka suffered from diarrhoea as floodlwaters left mud and sewage 35cm of rain fell in 1 day on 13 th Sept Death toll rose to 750 Airport, roads and railways flooded Bridges destroyed $7billion damage Rice crop destroyed along with food supplies – vegetables Cash crops – jute and sugar Textbook page 115
Is flooding in Bangladesh always a bad thing?
During the monsoon, between 30% and 50% of the entire country is flooded.
The flood waters:
Replenish groundwater reserves
Provide nutrient rich sediment for farming
Reduce the need for artificial fertilisers
Bangladesh GNP US$ 380 per capita
Short term concern is always for health survival and suffering of people affected.
A heavy reliance is placed upon emergency aid – food, drinking water medicines, plastic sheets, boats
Assistance is provided from United Nations, governments, charities
Problem is distribution because so much of the country is underwater.
As flood water recedes it is easier to set up medical treatment centres, distribute water purification tablets and provide help with repairing homes and restarting economic activities
In 1989 the government of Bangladesh began working with a number of international agencies to produce a Flood Action Plan. This huge scheme contained 26 action points which it was hoped would provide a long term solution to the country's flooding problems.
Short Term Management
Boats to rescue people
Emergency supplies for food, water, tents and medicines
Fodder for livestock
Repair and rebuild houses, as well as services such as sewage etc
Aid from other countries
Long Term Management
Reduce Deforestation in Nepal & Himalayas
Build 7 large dams in Bangladesh to store excess water $30-$40 million and 40 yrs to complete
Build 5000 flood shelters to accommodate all the population
Build 350km of embankment - 7 metres high at a cost of $6 billion to reduce flooding along the main river channels
Create flood water storage areas
Develop an effective Flood Warning Scheme
How have decision makers respond to the flooding? The Flood Action Plan (FAP) was set up in 1990 supported by several wealthy countries and the World Bank. Its aim was to reduce the impact of the floods that occurred annually in Bangladesh. The FAP’s objectives were to set up regional planning groups to study and monitor local river processes, followed by hard engineering aproaches. This involved the construction of 3,500km of coastal and river embankments to protect the land and to protect from storm surges brought by cyclones. The project included building seven large dams partly to stop water from reaching the land and to provide up to 15 floodwater storage basins. Millions of dollars of aid were poured into the engineering projects but the scheme remains unfinished due to corruption and inadequate funding. As a result the FAP is not considered to have been a complete success. Over 3 million people have been killed by coastal flooding in the last 30 years. The first findings of the FAP in 1995 stated that, while the flood protection scheme was economically desirable for urban areas, it was not a good idea in rural areas, which are dependent upon fishing and farming .
What issues are faced in implementing strategies in countries like Bangladesh?
The Bangladeshi Government cannot afford the high maintenance costs of the scheme
The embankments are at risk of erosion from the rivers
River channelisation by FAP embankments has increased the risk of flood damage for downstream areas
An estimated 8 million people were forced to move due to the FAP. These were people who relied on farming and fishing to support themselves.
Whilst the embankments have been strengthened, increased in height and extended in many places, the FAP has come across several problems, such as:
A sustainable solution?
People have suggested that Bangladesh really needs a mixture of strategies involving flood forecasting and early warning schemes together with more well stocked flood shelters.
These projects would be cheaper and more appropriate for farming and fishing communities in rural areas and would be more in keeping with local knowledge, skills and income levels and thus more sustainable . They would also have the advantage of being less likely to damage the ecosystems.
Flooding in Bangladesh Your task: Imagine you are working as a volunteer for an aid agency such as Water Aid in Bangladesh during the floods of 2004. Write a letter home describing the situation in the floods in Bangladesh, its effects and responses to it. Try to make your account as real as possible so that the reader can imagine the experience. Include photo images, witness accounts and describe your own thoughts and feelings.
Use the following links to add detail to your account: