The 2006 monsoon season produced the worst flooding in Bangladesh's 27 year history with 70 percent of the country submerged in floodwaters, and one million hectares of cropland destroyed. Between 30 to 40 million of the population of 126 million were affected. Floodwaters inundated most of the country for more than two months, destroying schools, government offices, countless homes and bringing diseases like diarrhoea and hepatitis. Over 1,000 people were killed and millions left homeless without food or shelter.
Causes
Deforestation in Nepal is increasing the risk of flooding in Bangladesh. As trees are cut down it causes surface runoff to increase because the trees do not absorb the water. The water carries soil into the rivers which builds up the river bed, this process results in the river becoming shallower.
Monsoon winds blow from cold to warm regions because cold air takes up more space than warm air. Monsoons blow from the land toward the sea in winter and from the sea toward land in the summer. Monsoon rains occur in August and September; this heavy rainfall causes the Ganges, the Brahmaputra and the Meghma all to increase in depth. When all three increase at the same time it is very dangerous as at the confluence there will be a huge amount of water, consequently if other factors have happened then the river could overflow and become a flood.
Tropical Cyclones are areas of intensive low pressure known locally as hurricanes or typhoons. Tropical Cyclones are the cause of coastal flooding in Bangladesh, they occur between July and October. They tend to develop:
- Over warm tropical oceans, where sea temperatures exceed 27C over a vast area, and where there is a considerable depth of warm water.
- In late summer and early autumn, when sea temperatures are at their highest.
- Between latitudes 5 degrees north and 20 degrees south of the equator.
Global warming is caused when carbon dioxide and other pollutants are released into the atmosphere. Carbon dioxide is the most important single factor in global warming. It is produced by road vehicles and by burning fossil fuels. This creates the world’s average temperature to increase, this results in snow on mountains like the Himalayas to melt slightly. The water from the melted snow in the Himalayas runs off into the Ganges, the Brahmaputra and the Meghma, resulting in the rivers carrying more water.
The people in Bangladesh rely on yearly floods to help them in their everyday lives, however when abnormal floods occur this causes great destruction. By researching information on causes of flooding in Bangladesh I can conclude that there is not one single factor for the abnormal flooding in Bangladesh, it is a result of a number of things. They can form when monsoon rains and tropical cyclones take place at the same time, also the constant affect of deforestation and global warming do not help. Deforestation brings silt to the rivers causing it to become shallower. Global warming causes mountains to melt which then causes the rivers to become deeper. Monsoon rains and Tropical Cyclones also cause the rivers to increase in depth. When everything combines, the rivers break their banks and this results in destructive flooding.
Solutions
Building 7 metre embankments all along the rivers channel would help to prevent flooding in Bangladesh, because the river would be able to hold more water. This project would also provide jobs for people living in Bangladesh. However when abnormal floods occur the water would break out of the banks and the high banks would stop the water being recalled back into the river. This water outside of the river would become stagnant. and are among main dangers of stagnant water, which can become a breeding ground for the that transmit these diseases, also over time the embankments would gragually erode. Vijay Patel quotes, “I believe 7 metre embankments will prevent abnormal floods because it is proven that the rivers do not rise above 700 cm.”
Artificial Levees would also help to prevent flooding in Bangladesh, levees convert an average river into having a v-shaped base. This will cause the river to flow faster, I know this because the source of a river is the fastest flowing, and a source has a v-shaped base. On the down side artificial levees are vey expensive and difficult to build. Guupreet Kanejah quotes, “As artificial levees cause rivers to flow faster, it causes the water in the river to not gather and prevent flooding, so in my opinion building artificial levees would be the best way to prevent flooding in Bangladesh.”
To build large protection buildings on stilts. They would be able to hold up to 1000 people and shelter animals. During an abnormal flood people could go there, they would be safe from drowning. Although in the past some similar buildings on stilts have been swept away by floods. Dipak Giyawdi quotes,“Although in the past buildings on stilts have been washed away I propose that new ones are built of a higher quality, this would not prevent flooding but it would defiantly stop the deaths of people during a flood.”
Building tube wells which would protect fresh water supplies during floods. Normally floods ruin all the water in well however this proposal would keep the water fresh and usable after floods. A disadvantage to this proposal is that the wells would have to be cleaned and looked after frequently. Rehman Sabhan quotes, “In my views survival is essential and survival is not possible without fresh water and previously during floods all wells in Bangladesh that contain fresh water are ruined, by installing tube wells fresh water will be preserved.”
Afforestation is the process of converting open land into a forest by planting trees or their seeds. Afforestation is the reverse of deforestation, instead of helping to cause floods it will help to prevent flooding in Bangladesh. The roots of the trees will hold the earth together and stop it eroding, preventing mudslides. Jane Growno quotes,”Mudslides and erosion help flooding in Bangladesh to occur, afforestation will halt these factors, consequently stopping flooding.”
In my opinion I feel that buildings on stilts and tube wells would be best to build in order to prevent flooding in Bangladesh, both do not affect the risk of flooding but they do benefit people’s health and more importantly their lives. The buildings give a place for people to go when floods occur, if people in danger during a flood go to these buildings then they will hopefully not drown or get injured.
The tube wells will preserve fresh water whilst floods are happening, after the floods the water in the wells will still be fresh and good to drink. So the water in the wells will not harm any one when it is drunk after, people have caught fatal diseases in the past after floods from drinking the infected water and they will continue to become infected by the water if tube wells are not built. Buildings on stilts and tube wells would have a good effect on Bangladesh, they would decrease the number of deaths during a flood, people would not drown and people would not catch fatal diseases. I have chosen these solutons to stop deathes by flooding, of course stoping the floods would obviously be the best solution but in my opinion none of the flood action plans; afforestation, artificial levees and embankments will not stop flooding, the embankments, however tall they are will eventually get washed away by erosion. Afforestation will take too long for the trees and their roots to grow big enough in order to stop flooding in the mean time many floods will occur, anyway Bangladeshi people have cut down the trees in the past, they might cut these one’s down as well. The problem with artificial levees is that they require substantial engineering and in my opinion Bangladesh do not have enough money to build artificial levees on all of the rivers which flow through Bangladesh, also artificial levees involve a vast amount of complxed building and I feel that the Bangladeshi people would not be able to handle the construction, so Bangladesh may have to pay special builders to help, these people would want to be paid for their work and as the Bangladeshi government would of already spent a lot of money on the material for artifiacial levees they would not be happy in paying more money for the building. This is why I have not chosen artificial levees, afforestation or embankments as a solution.
