Flooding case studies (effects and causes)

Cumbria UK 2009
1. the flooding lasted over one week. many areas within cumbia were flooded a total area of about 6000km
2. Causes
  1. Human
    1. Cockemouth was built on a floodplain very close to the river Derwent. urbanization increased the risk of flooding.
    2. there was a bridge across the river at gote road which could have a damming effect increasing friction. this reduces the rivers efficiency at this point. debris could have been caught at this point making the problem worse.
    3. Some people claimed that poor river management of the whole area allowed too much silt to build up and too much vegetation to grow on the banks and increase friction making it worse.
    4. some believe that the effects of global warming contributed it the floods as it is thought to increase the frequency of flooding events
  2. Physical
    1. Heaviest rainfall recorded in the England (314 mm in 24 hours)
    2. Prolonged rainfall 400mm in 72 hours
      1. the ground was also already saturated from weeks of heavy rain before the event
    3. Cockemouth, an area that received severe flooding was located at the confluence of 2 rivers where a tributary joins the River Derwent
    4. There is a more pronounced meander just downstream of the confluence which would have decreased the rivers ability to move water away quickly
    5. Cockemouth was built on a floodplain. (meant for flooding
3. effects
  1. Short term
    1. economic
      1. 20 road bridges, and over 200 footbridges. this will have to be rebuilt which will have a great cost. because of this, there may also be a lack of tourism
    2. social
      1. more than 500 people had to spend the night with relatives and friends or in emergency shelters after the floods.
      2. 1 person was swept away and killed when the bridge collapsed
      3. 20 bridges, and over 200 footbridges were destroyed. this means short detours are now lengthy detours
  2. Long term
    1. economic
      1. There was a great damage to homes, businesses and infrastructure
Pakistan 2010
1. Causes
  1. physical
    1. prolonged and heavy rainfall E.G 274mm fell in 24 hours in Peshwar on July 29th 2010. more than half the normal monsoon rains fell in only a week instead of 3 months
    2. Unusual conditions in the polar jet stream ( a fast moving air current that exists in the north of Pakistan) were thought to have bought heavy rainfall along with with the summer monsoon rain
    3. although not to the same extent, there is the river Indus floods annually
    4. a lot of sediment and mud from the Himalayas build up the channels making it more prone to flooding
    5. Scientist Mike Lockwood published a study showing the unusual behaviour of the jet stream may have been caused by the sun.
  2. Human
    1. too many people live close to the rivers to gain access to its resources such as water and fresh alluvial soils
    2. Two thirds of people in Pakistan depend on farming for income leaving them vulnerable to floods that result in a loss of livehood as well as homes
    3. the flood area spread into densely populated and poverty stricken urban areas of south pakistan
    4. the country's poor infrastructure prevented rescue teams from getting to those who needed help and emergency aid.
    5. Global warming may have strengthened the monsoon rains
    6. Deforestation meant there was a greater flood risk as more water and sediment will reach the river more quickly
2. Effects
  1. economic impacts
    1. 100s of bridges and 200 health facilities were damaged or destroyed reducing millions of healthcare for survivors in filthy conditions
    2. there was a total economic damage of 10billion (10% og GPD) damage to infrastructure alone, power plants, telecommunications, dams
  2. social impacts
    1. Up to 20 million people were thought to have been injured or made homeless by the floods
    2. Death toll was estimated to have reached 20000
    3. The World health organization estimated up to 10 million people had unsafe water
    4. 11000 schools has interrupted the education of an entire generation of children

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Flooding case studies (effects and causes)

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	Criado por Aidan S.G mais de 8 anos atrás