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

The flood hazard is due to its geography: the country is one huge delta Floodplain contains 250 perennial rivers, of which 56 originate outside the country (Tibet, Bhutan, India and Nepal) Only 7,5% of the total catchment area is within the country and 90% of discharge originates elsewhere

There are three main rivers in Bangladesh The Ganges, whose lower course is known as the Padma / basin area 1,1 million km, lenght 2478 km, average maximum discharge cumecs The Brahmaputra, whose lower reaches are known as the Jamuna / basin area 0,9 km, lenght 2900 km, average discharge cumecs The Meghna, east of the Padma-Jumana area, lenght 800 km, half of which lies in Bangladesh

Influence on inhabitants Flooding is part of the normal life for the people in Bangladesh Farming is finely tuned to sesional variations in discharge, and damage only occurs by natural disasters such as floods and cyclones, which are unexpected

The types of floods Flash floods carry a heavy sediment load, raising the level of river beds, and are caused by heavy monsoon rains falling on mountains and hill next to the floodplain River floods occur between May and September as a result of heavy regional storms or melting of the Himalayan snowpacks Rainfall floods result from localised precipitation during the monsoon rains, mostly in low-lying areas Cyclonic floods are sea floods and occur when cyclones from the Bay of Bengal create a storm surge which moves inland

The human causes of the floods Deforestation- the forests play a major role in the hydrology of the upland drainage basins absorbing water from the ground, binding the soil particles and reducing the impact of rain droplets on the ground surface. The removal of the forest cover has reduced interception and increased landslides, soil erosion and overland flow. It has been estimated that soil is being lost 400 times faster in deforested areas and is raising the river bed of the Brahmaputra by 5cm per year Dam building- the building of the Farraka Dam in India in 1971 is blamed for the raising of the river bed of the Hooghley River, a tributary of the Ganges. During the dry season the dam reduces the discharge of the river encouraging sedimentation on the river bed and increasing the risk of flooding. Urbanization- in Bangladesh recent development schemes involving the construction of the networks of roads and embankments have probably added obstacles to the free drainage of water from the land

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

Solutions to the flood hazard Various ideas have been put forward to reduce flooding and vulnerability to catastrophic events in Bangladesh Flood action plan sponsored by World Bank which involved: surveying of all main rivers and flood areas, raising embankments on west bank of the Brahmaputra river. Upgrading and linking of embankments on the east bank. five projects using mathematical models and remote sensing to model drainage basin flows. studies of economic, enviromental and social problems Flood forecasting with the aim of increasing radar stations in the hills and developing microwave links to a flood forecasting centre Controlled flooding where land, divided into compartments, can receive flood waters through sluice gates Coastel embankments and polders

... Self-help “flood-proofing“ which means the development of irrigated agrivulture during the dry season to avoid the monsoon risk, plus escape centres o high ground, specially designed school buildings, elevated roadds and market-places. Dredging the channels- but this is too expensive and the channels would soon become choked again in one season. Special bunds (embankment) o protect the capital city Dhaka Dam construction upstream and groundwater abstraction to crceate storage in the soil for monsoon rains

The impact of the flooding in 1998

The flooding in 1998 flooded over 57% of the land area Over 1000 people were killed and millions made homeless In Assam in the north-east more than one million people lost their homes in the Nalbari district 240 villages were submerged Large amounts of farmland and many properties were washed away An embankment protecting Sandwip, a large coastal island, was breached by a high tide marooning 1200 families Acute shortages of drinking water and food Infections affected large numbers of people along with outbreaks of diarrhoea and other diseases Overall the floods of 1998 cost country almost $1 billion $1 billion

The short-term response to the floods: By the Bangladesh government a) Distributed money and 400 tonnes of rice b) Provided relief supplies of fresh water and sanitation services c) Appealed for national unity and calm in the wake of the disaster and the general strike which took place in response to the flooding and accusations that the government failed to get basic goods to the people affected

By the governments of other countries Many countries around the world gave aid to Bangladesh during the flood disaste. Some of the donors included: Many countries around the world gave aid to Bangladesh during the flood disaste. Some of the donors included: The UK with steel bridge materials and million tonnes of wheat The UK with steel bridge materials and million tonnes of wheat Canada with million tonnes of wheat and money for medicines, water tablets, house repair, sanitation and for rehabilitation of farming and fishing Canada with million tonnes of wheat and money for medicines, water tablets, house repair, sanitation and for rehabilitation of farming and fishing Egypt with money for medicine Egypt with money for medicine Saudi Arabia sent tw cargo planes with food, medicines, blankets and tents Saudi Arabia sent tw cargo planes with food, medicines, blankets and tents

By The Disaster Forum (a network of aid agencies)  Provided boats to rescue people and move them and their belongings to higher land  Supplied medicines to treat and prevent the spread of diseases  Médecins Sans Frontiéres used six mobile teams in boats to travel around in one district where the population was literally living on the water  Supplied clean drinking water by repairing wells  Monitored the health situation and set up a mmedical treatment centre  Distributed fodder for livestock  Distributed food, plastic sheeting and water purification tablets  Planned a rehabilitation programme to repair and construct housing and sanitation

Conclusion Conclusion Managing the flood hazard is a challange for government and hydraulic engineers. In Bangladesh there is still uncertaintly over the main causes of the flood hazard, and further research is required to identify important factors and the effects of proposed structural solutions. Building embankments and bunds is particularly controversial: they can prevent floodwaters draining 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 fishing for their livelihood. Bangladesh faces triple problems in the future: sea level 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 of the shore, resulting in a 26% reduction of habitate land with 27% of the population displaced and GDP reduced by two-thirds.