River case studies
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?- Created by: Charlotte Walker
- Created on: 05-05-13 09:59
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- Rivers - Case studies
- Flooding
- Pakistan 2010
- Physical causes
- Heavy rainfall - 278mm over 24hrs
- Unusual conditions in the polar jet stream caused rains over previous months
- The river Indus carries a lot of sediment from the Himalayas
- Human causes
- Urbanisation - impermeable surfaces increase surface flow
- Deforestation in the Himalayas - logs stored in reservoirs caused more damage when released
- Many people live next to the river for use of its fertile alluvial soils
- 2/3rds of population depend on farming
- Consequences
- 2000 deaths
- 20 million homeless
- 1.2 million livestock lost - 6 million poultry lost
- $10bn cost - $7bn in infrastructure alone
- Farming hugely impacted
- 11,000 schools damaged , 100's of bridges, 200 healthcare centres
- Fact file
- 1/5th of Pakistan flooded - 69,000 km of fertile land flooded
- GDP per capita $3000
- Flooding lasted 3 weeks
- 170 million depend upon the river Indus
- Responses
- Emergency shelter for 900,000
- $230 given to returning families and food packages for 1 month
- Only 56% of the $1.96 bn asked for was given in aid - DONOR FATIGUE
- Pakistan army was criticised for being slow to give aid
- Physical causes
- Cumbria 2009
- Physical causes
- Heavy rains 314mm in 24hrs
- Prolonged rainfall - weeks of heavy rain
- Flood defences only protected up to a 1 in 100 year flood
- Human causes
- Urbanisation - more impermeable surfaces means shorter lag time
- Cockermouth was built on a flood plain
- River had not been dredged of sediment for a long time
- Fact file
- GDP per capita $ 38,000
- 1 in 1000 year flood
- Flooding lasted 1 week
- Consequences
- 500 people had to stay with relatives/ emergency shelter
- 1 death
- £276million bill
- cost to tourism £15million
- 20 road bridges destroyed,100's of footpath bridges
- 18 schools shut
- Responses
- £1 million clean up, £5.4 million to fix roads
- Army rebuilt many bridges, lifeboats used to resque people from homes
- Physical causes
- Pakistan 2010
- Flood defences
- Hard Engineering - 3 Gorges Dam
- Fact file
- Yangtze river, 3rd longest in the world - seasonal flooding in June/August
- Biggest dam in the world - 101m high, can hold 22km of flood water
- 1954 flood killed 33,000 people and 18million were made homeless
- 3600km of levees on river bank
- Positives
- Largest hydroelectric station in the world - supplies 3% of Chinas electricity
- Larger boats can navigate the river easily due to a deeper river channel
- Increased trade
- Can resist 1 in 100 year flood
- Negatives
- Reservoir has flooded 13 cities, 1000+ villages, 2 million had to be relocated
- The yangtze river carries a lot of sediment - build up of this could lead to dam failiure
- Destroys habitats and endangers species
- Increased erosion and landslides
- Fact file
- Soft engineering - Abingdon
- Fact file
- South- east England - built on the floodplains of the river Ock and the river Thames
- Regular flooding occurs - July 2007, 660 properties flooded
- Hard engineering options were too expensive and possibility of flooding downstream
- Defences
- Gravel soakaways on the A34
- Riprarian buffers on the river banks - trees lining banks
- Low value land allowed to flood i.e sports grounds
- Planning restrictions - Tesco had to install permeable tarmac surface for the new extension
- 24 hr flood warning service - advice on the internet about flood
- Fact file
- Hard Engineering - 3 Gorges Dam
- Flooding
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