Figure 1ASource:. www.acc-tv.com/images/wjla/news/envna_myanmarcyclone
On 2 May 2008 tropical cyclone Nargis hit the coast of Myanmar and devastated large parts of the low-lying Irrawaddy delta. Winds exceeding 190 kilometres per hour ripped through the Myanmar’s biggest city Yangon for more than ten hours. Homes were flattened, more sturdy structures damaged, trees uprooted and power lines downed. In rural parts of the country up to 95 per cent of homes were wiped off the face of the earth. There was an estimated loss of
146 000 lives.
Figure 1B
Source: www.ifrc.org
1. Figure 1A is a map showing the path of Cyclone Nargis which caused a natural disaster in Myanmar on 2 May 2008. Figure 1B is a short write–up on the aftermath of Cyclone Nargis on the southern coastal areas of Myanmar.
a) (i) Name the natural disaster related to tropical cyclone Nargis that happened to Myanmar.[1]
(ii) What evidence from Figure 1B suggest that the destruction caused by nature, Cyclone Nargis, was severe? [5]
(iii)Suggest 3 other natural causes that could have contributed to the severity of the natural disaster .[3]
b)What are some human activities that are likely to have contributed to the severity of the destruction brought about by Cyclone Nargis. Support your answer with examples.[8]
Suggested Answers
a(i) Name the natural disaster related to tropical cyclone Nargis that happened to Myanmar.[1]
Natural Disaster related to Cyclone Nargis or any tropical storm is FLOOD. ( 1)
(ii) What evidence from Figure 1B suggest that the destruction caused by nature, Cyclone Nargis, was severe? [5]
Evidence from write up pointing to the severity of destruction
· Estimate loss of lives was 146 000
· Flooding of large part of low lying Irrawady delta caused by strong wind pushing the waves inland making the floods more severe because Cyclone Nargis would have deposited a lot of rainwater as all tropical storms do.
· Strong wind tore away homes in Yangon the capital city.
· Rural area 95 % of homes ripped off- millions of people loss their homes
· Trees uprooted showing the strength of the storm
· Power lines fallen could have caused death by electrification of people in the vicinity .
[must infer that large number of people died. Must infer that urban areas tend to have more people of which Yangon is one of the places that the cyclone Nargis Swept through dumping lots of Rainfall..
(iii)Suggest 3 other natural causes that could have contributed to the severity of the natural disaster .[3]
· Melting of snow from the Himalayan mountains caused River Irrawady to swell and flood the banks.
· The floodplains of Irrawady delta are too low-lying resulting in floods whenever there is heavy rain .
· Rivers channel bed has become shallow due to heavy silting.
· Storm surge resulting from the strong storm winds .
b)What are some human activities that are likely to have contributed to the severity of the destruction brought about by Cyclone Nargis. Support your answer with examples.[8]
Clearing of forests
· Satellite pictures of Irrawaddy delta shows that deforestation on a large scale has caused heavy silting of River Irrawaddy and the extension of the delta further out into the Bay of Bengal .(1)
-Deforestation Increase surface runoff when less trees intercept the rainwater in tropical climate. (1)
--Heavy silting of river bed is the result of increased rate of erosion on bare slopes after deforestation. There are no roots to bind the soil on slopes. (1)
-Silting of river beds would mean the riverbed is shallow and hence has less capacity to discharge water into the sea giving rise to flooding when there is a storm surge (1) when strong wind pushes the sea water in inland through the delta region causing severe flooding
· Rapid growth in population and the fertile alluvial soil of Irrawaddy delta have attracted many poor people to settle in the delta region to practice subsistence farming. A delta being flat would have spurred growth of transportation resulting in large migration of people (1) to the delta region.
So when the tropical storm hit the area, more people are
affected as compared to a smaller population.(1)
· Urban development
Myanmar being an LDC would mean there is rapid urbanization because of rural-urban migration.
More roads and concrete pavement would be constructed to cater to heavy human traffic. (1)
Concrete pavement increases surface run off (1) resulting in rainwater flowing into the river channel quicker than a forested area. Result is severe flooding in urban areas
· Enhanced greenhouse effect
-Global warming has increased the intensity of tropical storms in recent years resulting in greater destruction e.g Katrina of 2005 hit Florida and New Orleans in USA.
So is the intensity of Nargis…the most powerful Tropical storm that Myanmar has ever recorded.(1)
-Increased atmospheric temperature has caused greater rate of melting of snow in the Himalayas (1)which is the source of Irrawaddy River. The greater melting of snow means more water in river channel. When the greater volume of water in the channel meets with the storm surge, there is a double whammy. Flooding will be very severe.
Award marks for efforts in explaining processes involved e.g deforestation and erosion, increased surface runoff and silting of rivers.
Award marks for candidate who show application of knowledge of rapid snow melting due to global warming and silting plus the dumping of rain by the storm that have contributed to the severity of storm- a case of nature and man creating this horrendous event.
c) Evaluate the effectiveness of management strategies that can reduce the negative impact of floods.[8]
Strategies in reducing negative impact of floods.
1.Building artificial levées and dykes
Walls of sand, stone and concrete are built along river banks to increase the capacity of the river to hold water.
2.Construction of dams
Dams control the amount of water flowing into the rivers, using gates to hold back or release water.
3.Building control
Maps showing flood-prone areas provide information for developers to ensure that floods would not affect the buildings they construct.
4.Watershed management
Programmes can be implemented to manage the entire watershed by conserving vegetation cover or re-planting trees so as to reduce surface run-off.
5.Flood insurance
Residents in flood-prone areas can have their property insured against flood, so that they can afford to repair their property if floods occur.
6.Monitoring and education
Scientists can use modern technology to monitor weather patterns and warn of floods in advance.
Citizens can be educated on how to react when floods occur.
7.Post-flood management measures
Plans can be made by authorities to evacuate victims when floods occur.
Foreign aid may also be offered to help flood victims.
Level 1 (0-3m)
States/ describes the measures of flood control
Provides no/ brief examples with little details of how effective those measures are in flood control
Level 2 (4-6m)
Candidate gave his judgement statement such as ‘to a certain extent’ and gave reason(s) why he said so.
Provides explanations with 2 details but provides one –sided e.g only hardwares like building of dams, dykes, artificial levees and did not give the software measures like educating people on deforestation impact and what to do in a flood.
Citing of examples like Singapore River that had undergone resectioning to deepen and widen the river channel to increase its capacity to discharge storm water.
Level 3 (7-8m)
Judgement statement and indicating how some strategies are more feasible in Less Developed Countries because of lack of funds to construct or maintain the hardwares like construction of dykes, dams
Provide more than 3 measures and weigh the feasibility of each measure especially in the context of LDCs.
Application of knowledge of how corruption of govt officials can derail flood management by diverting funds meant for such flood management into their own pocket
how poverty can make buying of flood insurance a non feasible measure e.g in LDCS like Myanmar.
No comments:
Post a Comment