JoeComins
11-10-2006, 02:07 PM
Can flooding in Bangladesh by prevented against flooding the future?
By looking at the causes and consequences of the 1988 floods, we are able to foresee the any possibilities in the future. By looking at what caused it, we may also be able to spot an effective flood prevention method which will control flooding, but at the same time be environmentally friendly, considering the consequences and upsides to these, and to see which would be most likely to be implemented with the current financial status of Bangladesh.
Geographical View on Bangladesh
Bangladesh is situated on the low lying ground of the Ganges Delta, which provides Bangladesh with some of the most highly fertile soil in the world, which is caused by the deposits of Alluvium from the river.
Most of Bangladesh is within 10 meters of the sea level, as with a 1 meter sea-level rise, it is estimated that a further 10% of Bangladesh would be flooded. The highest point in Bangladesh is the Mowdok range, rising to 1,052 meters in the South-East of the country.
As Bangladesh is on the Tropic of Cancer, the climate from October to March is tropical, but still hot and humid from March to July. A monsoon occurs from July to October with the changes in temperature, which is when the majority of the flooding will happen, due to flash, heavy rainfall. Tropical Cyclones, Tornadoes and Tidal Bored may also occur, along side extreme flooding.
Why did Bangladesh flood abnormally in 1988?
In 1988, the abnormal flooding was a result of several factors, which all incurred at a similar time.
By many Geographers, the heavy monsoons, combined with the synchronisation on the flood peaks of several rivers are considered to be the main factors of the flood. As the heavy monsoon would have quickly saturated the soil, the heavy rainfall would have run-off, and into the rivers, which would fill those to the maximum capacity, resulting in the river over-flowing and bursting its banks, making any excess water run over the ground.
Even though these were some of the main causes, under-lying factors do not deserve over-looking.
One of these was the depth of the rivers. Due to recent floods, the rivers had accumulated an extra layer of silt, which meant the river was shallower, which meant it would burst through its banks more easily, as it would have took less water to fill up.
Another factor was the amount of silt which had previously been washed onto the land from previous flooding – Which had been very little. If more silt which had collected on the river-bed had been moved by the floods onto the land, the rivers would have been deeper, so would have held more water, while at the same time, the land would have been higher due to the extra levels of silt. As it was, the rivers were shallower than they could have been, and the ground level wasn’t as high as it could have been, which could have significantly increase any flood risks.
Deforestation upstream was another factor; this enabled water to reach the rivers much more quickly, as less trees meant that less infiltration would have taken place. With more water reaching the river at the same time would result in the same way; the water level being too high, and the river being full to its capacity.
High Flood Records
Flooding in 1988: 89,970 sq. km or 61% of Bangladesh
Flooding in 1998: 100,250 sq. km or 68% of Bangladesh
What impact did the 1988 floods do to Bangladesh?
The floods covered 61% of Bangladesh, directly effecting two thirds of the population. Only the very tops of some trees and the peaks of buildings could be seen over the water level. In Dhaka alone, the water was 2 meters deep, and covered 75% of the city.
The official death toll of 2379 people, but many more were reported missing and never found or unaccounted for; others drowned. A small number of people died from snake bites, as the snakes were seeking refuge in the same way as the humans. To add to this toll, many people died of Cholera, which can be fatal within 12 hours, or Dynasty. Both of which is carried in the water supply, which was contaminated from the water getting into the sewage system, and moving it around in the water. These diseases in England were eradicated with the Plague, but in other countries, money and time is the issue as to why these haven’t been stopped.
More effects came in the form of human depravation. There were many shortages of food, medicine, and safe refuge. While people were starving, over 2 million tonnes of rice, or a quarter of their rice stock were destroyed. The majority of Jute, Sugar cane and vegetable crops were lost, alone side 0.5 million cattle and poultry.
Thousands of kilometres of roads, bridges and railways were destroyed, further preventing food from rescue workers from getting through. The countries 6-8 helicopters could only carry 2 tonnes of food at a time. This meant that if all of the helicopters were working flat out, they could only carry from 12 to 16 tonnes of food at a time, and when 45 million people are starving, this is very little.
Flood Prevention
Flooding is a natural phenomenon, which cannot be fully prevented. Most of the Bangladeshi farmers disregarded the idea of complete flood control, as it would take sections of their land, and they would not get the fertile soil. The flood control measures should be directed at the intensity of the flooding, rather than total prevention. The people in Bangladesh should also adapt around the flooding, as by living on a delta, you cannot totally prevent this. To adapt around the flooding, the structure of the houses could be changed to compensate for the flood, such as the government making “stilts” on which their houses would sit. If there were several concrete posts in one area which large houses could be built on to fit a number of families in, and then a strong walkway to a central plinth, this would mean that that area would be safe from flooding. However, this method would ruin the landscape, and be impractical, as well as being too expensive. This is just one idea.
My ideal solution to the flooding, which could be implemented over a lengthy period of time, would be to take the following steps:
1.Dredging the rivers
By dredging the rivers, the rivers would become deeper, and as a result hold more water, which means less would run over the land, causing the currently abnormal floods to be significantly lighter.
2.Re-Excavation of old rivers and/or lakes
As with dredging the rivers, this would mean that the soil excavated from these would make the level of the land higher, and would mean more space for water to fill and not over-flow onto the land, and give the same effect as dredging the rivers, but on a much bigger scale. Even though the countries economy may be suffering, and as it’s a LEDC, the money could come from fund raising, and charities send millions of pounds each year to help these people.
3.Efficient storm sewer systems
An efficient storm sewer system would stop the sewage leaking out into the flooded areas, and stop diseases such as Cholera and Dynasty. This would also mean that the flood water, if there was any after these above points were put in place, would be cleaner, and not carry disease.
4.Urbanization Management
Strict management of urbanization would mean that people would not be aloud to live in areas which would be of a high flood risk, and developers would not be able to build in place which would give a significant decrease the lag-time, as this would mean more water would still be getting to the rivers at the same time, which may cause it to overflow, in which case, the above points would be relatively pointless.
Why are these actions so dramatic, and so important to Bangladesh?
These measures are so extreme and have to be implemented, as with a 6°C increase the earths temperature, which has increased and decreased naturally for millions of years, Bangladesh’s 3 main rivers would have more water pass through them, and inevitably mean that 20 to 40% more of Bangladesh would flood annually. There would also be a steep increase in deeply flooded land - that covered by more than 1.8 meters of water for nine months of the year. Of the 3.1 million hectares that floods each year, 42% is already deeply flooded. That will climb to 55% if temperatures rise by 6 °C.
Is this plausible with the current economy of Bangladesh?
As Bangladesh receives a lot of aid from MEDC’s, if they could receive more, or keep some for these projects, I think some of these would be plausible within 100 years. As Bangladesh is a LEDC, money cannot be used as freely, but if by selling what resources they have, or harness the power of the electricity from the rivers which could be sold abroad, they may be able to afford the Flood Control.
Also, there is a FAP or a Flood Action Plan already in place which gets funding to help the country, but waste it on embankments which aren’t very effective, as it keeps rainwater in area more so than keeping the river water in. It also keeps the fertile silt in the river water off the land, which the farmers need it on to enhance their soil and growing potential.
Word Count: 1604 words
By looking at the causes and consequences of the 1988 floods, we are able to foresee the any possibilities in the future. By looking at what caused it, we may also be able to spot an effective flood prevention method which will control flooding, but at the same time be environmentally friendly, considering the consequences and upsides to these, and to see which would be most likely to be implemented with the current financial status of Bangladesh.
Geographical View on Bangladesh
Bangladesh is situated on the low lying ground of the Ganges Delta, which provides Bangladesh with some of the most highly fertile soil in the world, which is caused by the deposits of Alluvium from the river.
Most of Bangladesh is within 10 meters of the sea level, as with a 1 meter sea-level rise, it is estimated that a further 10% of Bangladesh would be flooded. The highest point in Bangladesh is the Mowdok range, rising to 1,052 meters in the South-East of the country.
As Bangladesh is on the Tropic of Cancer, the climate from October to March is tropical, but still hot and humid from March to July. A monsoon occurs from July to October with the changes in temperature, which is when the majority of the flooding will happen, due to flash, heavy rainfall. Tropical Cyclones, Tornadoes and Tidal Bored may also occur, along side extreme flooding.
Why did Bangladesh flood abnormally in 1988?
In 1988, the abnormal flooding was a result of several factors, which all incurred at a similar time.
By many Geographers, the heavy monsoons, combined with the synchronisation on the flood peaks of several rivers are considered to be the main factors of the flood. As the heavy monsoon would have quickly saturated the soil, the heavy rainfall would have run-off, and into the rivers, which would fill those to the maximum capacity, resulting in the river over-flowing and bursting its banks, making any excess water run over the ground.
Even though these were some of the main causes, under-lying factors do not deserve over-looking.
One of these was the depth of the rivers. Due to recent floods, the rivers had accumulated an extra layer of silt, which meant the river was shallower, which meant it would burst through its banks more easily, as it would have took less water to fill up.
Another factor was the amount of silt which had previously been washed onto the land from previous flooding – Which had been very little. If more silt which had collected on the river-bed had been moved by the floods onto the land, the rivers would have been deeper, so would have held more water, while at the same time, the land would have been higher due to the extra levels of silt. As it was, the rivers were shallower than they could have been, and the ground level wasn’t as high as it could have been, which could have significantly increase any flood risks.
Deforestation upstream was another factor; this enabled water to reach the rivers much more quickly, as less trees meant that less infiltration would have taken place. With more water reaching the river at the same time would result in the same way; the water level being too high, and the river being full to its capacity.
High Flood Records
Flooding in 1988: 89,970 sq. km or 61% of Bangladesh
Flooding in 1998: 100,250 sq. km or 68% of Bangladesh
What impact did the 1988 floods do to Bangladesh?
The floods covered 61% of Bangladesh, directly effecting two thirds of the population. Only the very tops of some trees and the peaks of buildings could be seen over the water level. In Dhaka alone, the water was 2 meters deep, and covered 75% of the city.
The official death toll of 2379 people, but many more were reported missing and never found or unaccounted for; others drowned. A small number of people died from snake bites, as the snakes were seeking refuge in the same way as the humans. To add to this toll, many people died of Cholera, which can be fatal within 12 hours, or Dynasty. Both of which is carried in the water supply, which was contaminated from the water getting into the sewage system, and moving it around in the water. These diseases in England were eradicated with the Plague, but in other countries, money and time is the issue as to why these haven’t been stopped.
More effects came in the form of human depravation. There were many shortages of food, medicine, and safe refuge. While people were starving, over 2 million tonnes of rice, or a quarter of their rice stock were destroyed. The majority of Jute, Sugar cane and vegetable crops were lost, alone side 0.5 million cattle and poultry.
Thousands of kilometres of roads, bridges and railways were destroyed, further preventing food from rescue workers from getting through. The countries 6-8 helicopters could only carry 2 tonnes of food at a time. This meant that if all of the helicopters were working flat out, they could only carry from 12 to 16 tonnes of food at a time, and when 45 million people are starving, this is very little.
Flood Prevention
Flooding is a natural phenomenon, which cannot be fully prevented. Most of the Bangladeshi farmers disregarded the idea of complete flood control, as it would take sections of their land, and they would not get the fertile soil. The flood control measures should be directed at the intensity of the flooding, rather than total prevention. The people in Bangladesh should also adapt around the flooding, as by living on a delta, you cannot totally prevent this. To adapt around the flooding, the structure of the houses could be changed to compensate for the flood, such as the government making “stilts” on which their houses would sit. If there were several concrete posts in one area which large houses could be built on to fit a number of families in, and then a strong walkway to a central plinth, this would mean that that area would be safe from flooding. However, this method would ruin the landscape, and be impractical, as well as being too expensive. This is just one idea.
My ideal solution to the flooding, which could be implemented over a lengthy period of time, would be to take the following steps:
1.Dredging the rivers
By dredging the rivers, the rivers would become deeper, and as a result hold more water, which means less would run over the land, causing the currently abnormal floods to be significantly lighter.
2.Re-Excavation of old rivers and/or lakes
As with dredging the rivers, this would mean that the soil excavated from these would make the level of the land higher, and would mean more space for water to fill and not over-flow onto the land, and give the same effect as dredging the rivers, but on a much bigger scale. Even though the countries economy may be suffering, and as it’s a LEDC, the money could come from fund raising, and charities send millions of pounds each year to help these people.
3.Efficient storm sewer systems
An efficient storm sewer system would stop the sewage leaking out into the flooded areas, and stop diseases such as Cholera and Dynasty. This would also mean that the flood water, if there was any after these above points were put in place, would be cleaner, and not carry disease.
4.Urbanization Management
Strict management of urbanization would mean that people would not be aloud to live in areas which would be of a high flood risk, and developers would not be able to build in place which would give a significant decrease the lag-time, as this would mean more water would still be getting to the rivers at the same time, which may cause it to overflow, in which case, the above points would be relatively pointless.
Why are these actions so dramatic, and so important to Bangladesh?
These measures are so extreme and have to be implemented, as with a 6°C increase the earths temperature, which has increased and decreased naturally for millions of years, Bangladesh’s 3 main rivers would have more water pass through them, and inevitably mean that 20 to 40% more of Bangladesh would flood annually. There would also be a steep increase in deeply flooded land - that covered by more than 1.8 meters of water for nine months of the year. Of the 3.1 million hectares that floods each year, 42% is already deeply flooded. That will climb to 55% if temperatures rise by 6 °C.
Is this plausible with the current economy of Bangladesh?
As Bangladesh receives a lot of aid from MEDC’s, if they could receive more, or keep some for these projects, I think some of these would be plausible within 100 years. As Bangladesh is a LEDC, money cannot be used as freely, but if by selling what resources they have, or harness the power of the electricity from the rivers which could be sold abroad, they may be able to afford the Flood Control.
Also, there is a FAP or a Flood Action Plan already in place which gets funding to help the country, but waste it on embankments which aren’t very effective, as it keeps rainwater in area more so than keeping the river water in. It also keeps the fertile silt in the river water off the land, which the farmers need it on to enhance their soil and growing potential.
Word Count: 1604 words