Bangladesh is a country in south-Bangladesh is a country in south-east Asia that suffers annual east Asia that suffers annual floodingfloodingIt is probably country affected by It is probably country affected by the most of floodsthe most of floodsThe floodwaters bring alluvial The floodwaters bring alluvial sediment which makes the delta sediment which makes the delta and floodplains very fertile but and floodplains very fertile but frequently is severe causing loss of frequently is severe causing loss of life and population sufferlife and population sufferExtreme poverty and geographic Extreme poverty and geographic pressure increase the sufferingpressure increase the sufferingMuch of the country´s budget must Much of the country´s budget must be used for recoverybe used for recovery

The flood hazard is due to The flood hazard is due to its geography: the country its geography: the country is one huge deltais one huge delta

Floodplain contains 250 Floodplain contains 250 perennial rivers, of which perennial rivers, of which 56 originate outside the 56 originate outside the country (Tibet, Bhutan, country (Tibet, Bhutan, India and Nepal)India and Nepal)

Only 7,5Only 7,5%% of the total of the total catchment area is within catchment area is within the country and 90the country and 90%% of of discharge originates discharge originates elsewhereelsewhere

There are three main rivers in There are three main rivers in BangladeshBangladesh

The GangesThe Ganges, whose lower course is known as the , whose lower course is known as the Padma / basin area 1,1 million km, lenght 2478 Padma / basin area 1,1 million km, lenght 2478 km, average maximum discharge 299 000 km, average maximum discharge 299 000 cumecscumecs

The BrahmaputraThe Brahmaputra, whose lower reaches are , whose lower reaches are known as the Jamuna / basin area 0,9 km, lenght known as the Jamuna / basin area 0,9 km, lenght 2900 km, average discharge 317 000 cumecs2900 km, average discharge 317 000 cumecs

The MeghnaThe Meghna, east of the Padma-Jumana area, , east of the Padma-Jumana area, lenght 800 km, half of which lies in Bangladesh lenght 800 km, half of which lies in Bangladesh

Influence on inhabitantsInfluence on inhabitants

Flooding is part of the normal life for the people in Flooding is part of the normal life for the people in BangladeshBangladesh

Farming is finely tuned to sesional variations in discharge, Farming is finely tuned to sesional variations in discharge, and damage only occurs by natural disasters such as floods and damage only occurs by natural disasters such as floods and cyclones, which are unexpected and cyclones, which are unexpected

The types of floodsThe types of floods

Flash floodsFlash floods carry a heavy sediment load, raising the level carry a heavy sediment load, raising the level of river beds, and are caused by heavy monsoon rains of river beds, and are caused by heavy monsoon rains falling on mountains and hill next to the floodplainfalling on mountains and hill next to the floodplain

River floodsRiver floods occur between May and September as a result occur between May and September as a result of heavy regional storms or melting of the Himalayan of heavy regional storms or melting of the Himalayan snowpackssnowpacks

Rainfall floodsRainfall floods result from localised precipitation during the result from localised precipitation during the monsoon rains, mostly in low-lying areasmonsoon rains, mostly in low-lying areas

Cyclonic floodsCyclonic floods are sea floods and occur when cyclones are sea floods and occur when cyclones from the Bay of Bengal create a storm surge which moves from the Bay of Bengal create a storm surge which moves inlandinland

The human causes of the floodsThe human causes of the floods

DeforestationDeforestation- the forests play - the forests play a major role in the hydrology a major role in the hydrology of the upland drainage basins of the upland drainage basins absorbing water from the absorbing water from the ground, binding the soil ground, binding the soil particles and reducing the particles and reducing the impact of rain droplets on the impact of rain droplets on the ground surface. The removal ground surface. The removal of the forest cover has of the forest cover has reduced interception and reduced interception and increased landslides, soil increased landslides, soil erosion and overland flow. It erosion and overland flow. It has been estimated that soil has been estimated that soil is being lost 400 times faster is being lost 400 times faster in deforested areas and is in deforested areas and is raising the river bed of the raising the river bed of the Brahmaputra by 5cm per yearBrahmaputra by 5cm per year

Dam buildingDam building- the building of - the building of the Farraka Dam in India in the Farraka Dam in India in 1971 is blamed for the raising 1971 is blamed for the raising of the river bed of the Hooghley of the river bed of the Hooghley River, a tributary of the River, a tributary of the Ganges. During the dry season Ganges. During the dry season the dam reduces the discharge the dam reduces the discharge of the river encouraging of the river encouraging sedimentation on the river bed sedimentation on the river bed and increasing the risk of and increasing the risk of flooding.flooding.UrbanizationUrbanization- in Bangladesh - in Bangladesh recent development schemes recent development schemes involving the construction of involving the construction of the networks of roads and the networks of roads and embankments have probably embankments have probably added obstacles to the free added obstacles to the free drainage of water from the landdrainage of water from the land

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Global warmingGlobal warming- some - some peoplpe attach considerable peoplpe attach considerable blame to global warming and blame to global warming and a rise in sea level. The a rise in sea level. The Bangladesh floods in 1998 Bangladesh floods in 1998 were notable for their long were notable for their long duration of 56 days. This was duration of 56 days. This was blamed by some on the higher blamed by some on the higher sea levels which meant that sea levels which meant that the surface water on the the surface water on the floodplain took longer to floodplain took longer to infiltrate. The same people infiltrate. The same people also attribute the especially also attribute the especially high rainfall in the Himalayas high rainfall in the Himalayas in 1998 to the increased global in 1998 to the increased global temperaturetemperature

Solutions to the flood hazardSolutions to the flood hazard

Various ideas have been put forward to reduce flooding and Various ideas have been put forward to reduce flooding and vulnerability to catastrophic events in Bangladeshvulnerability to catastrophic events in Bangladesh

Flood action plan 1990-1995 sponsored by World Bank which Flood action plan 1990-1995 sponsored by World Bank which involved: surveying of all main rivers and flood areas, raising involved: surveying of all main rivers and flood areas, raising embankments on west bank of the Brahmaputra river. Upgrading embankments on west bank of the Brahmaputra river. Upgrading and linking of embankments on the east bank. five projects using and linking of embankments on the east bank. five projects using mathematical models and remote sensing to model drainage basin mathematical models and remote sensing to model drainage basin flows. studies of economic, enviromental and social problemsflows. studies of economic, enviromental and social problems

Flood forecasting with the aim of increasing radar stations in the Flood forecasting with the aim of increasing radar stations in the hills and developing microwave links to a flood forecasting centrehills and developing microwave links to a flood forecasting centre

Controlled flooding where land, divided into compartments, can Controlled flooding where land, divided into compartments, can receive flood waters through sluice gatesreceive flood waters through sluice gates

Coastel embankments and poldersCoastel embankments and polders

......Self-help “flood-proofing“ which means Self-help “flood-proofing“ which means the development of irrigated agrivulture the development of irrigated agrivulture during the dry season to avoid the during the dry season to avoid the monsoon risk , plus escape centres o monsoon risk , plus escape centres o high ground, specially designed school high ground, specially designed school buildings, elevated roadds and market-buildings, elevated roadds and market-places.places.

Dredging the channels- but this is too Dredging the channels- but this is too expensive and the channels would soon expensive and the channels would soon become choked again in one season.become choked again in one season.

Special bunds (embankment) o protect Special bunds (embankment) o protect the capital city Dhakathe capital city Dhaka

Dam construction upstream and Dam construction upstream and groundwater abstraction to crceate groundwater abstraction to crceate storage in the soil for monsoon rainsstorage in the soil for monsoon rains

The impact of the flooding in 1998The impact of the flooding in 1998

The flooding in 1998 flooded The flooding in 1998 flooded over 57over 57%% of the land area of the land area

Over 1000 people were killed Over 1000 people were killed and millions made homeless and millions made homeless

In Assam in the north-east In Assam in the north-east more than one million people more than one million people lost their homes in the lost their homes in the Nalbari district 240 villages Nalbari district 240 villages were submergedwere submerged

Large amounts of farmland Large amounts of farmland and many properties were and many properties were washed awaywashed away

An embankment protecting An embankment protecting Sandwip, a large coastal Sandwip, a large coastal island, was breached by a high island, was breached by a high tide marooning 1200 familiestide marooning 1200 families

Acute shortages of drinking Acute shortages of drinking water and foodwater and food

Infections affected large Infections affected large numbers of people along with numbers of people along with outbreaks of diarrhoea and outbreaks of diarrhoea and other diseasesother diseases

Overall the floods of 1998 cost Overall the floods of 1998 cost country almost country almost

$$1 billion1 billion

The short-term response to the floods:The short-term response to the floods:

By the Bangladesh governmentBy the Bangladesh government

a)a) Distributed money and 400 tonnes of riceDistributed money and 400 tonnes of rice

b)b) Provided relief supplies of fresh water and Provided relief supplies of fresh water and sanitation servicessanitation services

c)c) Appealed for national unity and calm in the Appealed for national unity and calm in the wake of the disaster and the general strike wake of the disaster and the general strike which took place in response to the flooding and which took place in response to the flooding and accusations that the government failed to get accusations that the government failed to get basic goods to the people affectedbasic goods to the people affected

By the governments of other countriesBy the governments of other countries Many countries around the world gave aid to Bangladesh Many countries around the world gave aid to Bangladesh

during the flood disaste. Some of the donors included:during the flood disaste. Some of the donors included:

The UK with steel bridge materials and 100 000 million tonnes The UK with steel bridge materials and 100 000 million tonnes of wheatof wheat

Canada with 12500 million tonnes of wheat and money for Canada with 12500 million tonnes of wheat and money for medicines, water tablets, house repair, sanitation and for medicines, water tablets, house repair, sanitation and for rehabilitation of farming and fishingrehabilitation of farming and fishing

Egypt with money for medicineEgypt with money for medicine

Saudi Arabia sent tw cargo planes with food, medicines, Saudi Arabia sent tw cargo planes with food, medicines, blankets and tentsblankets and tents

By The Disaster Forum (a network of aid agencies)By The Disaster Forum (a network of aid agencies)

a)a) Provided boats to rescue Provided boats to rescue people and move them and people and move them and their belongings to higher their belongings to higher landland

b)b) Supplied medicines to treat Supplied medicines to treat and prevent the spread of and prevent the spread of diseasesdiseases

c)c) Médecins Sans Frontiéres Médecins Sans Frontiéres used six mobile teams in used six mobile teams in boats to travel around in one boats to travel around in one district where the population district where the population was literally living on the was literally living on the waterwater

d)d) Supplied clean drinking Supplied clean drinking water by repairing wellswater by repairing wells

a)a) Monitored the health Monitored the health situation and set up a situation and set up a mmedical treatment centremmedical treatment centre

b)b) Distributed fodder for Distributed fodder for livestocklivestock

c)c) Distributed food, plastic Distributed food, plastic sheeting and water sheeting and water purification tabletspurification tablets

d)d) Planned a rehabilitation Planned a rehabilitation programme to repair and programme to repair and construct housing and construct housing and sanitationsanitation

ConclusionConclusion

Managing the flood hazard is a challange for government Managing the flood hazard is a challange for government and hydraulic engineers. In Bangladesh there is still uncertaintly and hydraulic engineers. In Bangladesh there is still uncertaintly over the main causes of the flood hazard, and further research is over the main causes of the flood hazard, and further research is required to identify important factors and the effects of proposed required to identify important factors and the effects of proposed structural solutions. Building embankments and bunds is structural solutions. Building embankments and bunds is particularly controversial: they can prevent floodwaters draining particularly controversial: they can prevent floodwaters draining from fields and back into rivers, and they have an impact on fish from fields and back into rivers, and they have an impact on fish stocks, a vital resource in a country where 5 million depend on stocks, a vital resource in a country where 5 million depend on fishing for their livelihood.fishing for their livelihood.

Bangladesh faces triple problems in the future: sea level Bangladesh faces triple problems in the future: sea level rises, delta subsidence and reduced delta growth. The net effect rises, delta subsidence and reduced delta growth. The net effect by 2100 could be a 3 metre rise of the sea level and a 2 km retreat by 2100 could be a 3 metre rise of the sea level and a 2 km retreat of the shore, resulting in a 26of the shore, resulting in a 26%% reduction of habitate land with reduction of habitate land with 2727%% of the population displaced and GDP reduced by two-thirds. of the population displaced and GDP reduced by two-thirds.