Water on the land case studies

The River Clyde
1. 160 km long, flows through Soctland
2. Source= Southern Uplands region of Scotland (Lowther Hills), Mouth= estuary on west coast
3. meanders between Glasgow and Motherwell, Glasgow built on its floodplain
4. oxbow lake near village of Uddingston
5. The Falls of Clyde = 4 waterfalls
6. Interlocking spurs at Crawford
LEDC flood- Bangladesh
1. August 2007, Rivers Brahmaputra and Ganges, South Asia
2. Causes
  1. Physical
    1. Heavy rainfall- 900mm July- saturated the soil
    2. snowmelt from glaciers in Himalayan mountains
    3. peak discharge of both rivers happened at the same time
    4. most of the country is flood plain and delta of the two rivers
    5. 70% total area less than 1m above sea level
    6. heavy monsoon rains in summer and tropic cyclones
  2. Human
    1. growth in population leading to deforestation- more soil erosion and overland flow
    2. Farraka Dam raised river bed of Hoogly River (tributary of the Ganges)
3. Impacts
  1. Primary
    1. Over 2000 deaths
    2. 25 mil people made homeless
    3. factories closed, livestock killed
    4. 112,000 houses destroyed in India
    5. rivers polluted with rubbish and sewage
  2. Secondary
    1. children lost out on education, 4,000 schools affected
    2. 100,000 people caught water borne diseases: dysentery and diarrhoea
    3. flooded fields reduced Basmati rice yields- prices rose 10%
    4. farmers and factory workers became unemployed
4. Management
  1. flood forecasting and warning system
    1. warnings dont reach many rural communities
  2. man made levees- not properly maintained
  3. Immediate response
    1. blocked transport links prevented and slowed down evacuations attempted
    2. governments and international charities distribute food, water and medical aid
    3. rescue boats, medical treatment centres (water purification tablets UN)
  4. Long term response
    1. homes rebuilt on stilts
    2. repairing and maintaining levees
    3. help provided for repairing houses and restarting economic activities (farming and fishing)
MEDC flood- Boscastle
1. August 2004
2. Causes
  1. Physical
    1. 3 rivers, the V.a.l.e.n.c.y, Jordan and Paradise converge on the village of Boscastle
    2. Heavy rainfall, 3 million tonnes of water added to tiny drainage basin- infiltration-excess overland flow
    3. Soils already saturated from previous rainfall
    4. 3 river valleys steep and narrow
      1. soils are thin with limited storage capacity
    5. valley made of old hard sandstone- limited permeability- flashy rivers
    6. surrounding vegetation includes agriculatural land with limited interception storage
    7. rain coincided with high tide in the bay- restricted rate of exit of floodwater into the harbour
  2. Human
    1. settlement of Bosacastle on a flood plain
    2. no flood defences had yet been built
3. Impacts
  1. mainly short term, worst time of year when settlement population doubles due to tourism
  2. Infrastructure damage to buildings and services cost up to £2 million
  3. 4 footbridges along Valency valley washed away
  4. Social
    1. 1000 residents and visitors affected
    2. no fatalities
    3. 58 properties flooded- 4 demolished
    4. 84 wrecked cars, 32 still out at sea
4. management
  1. Immediate response
    1. excellent emergency services meant no lives lost
    2. 7 helicopters lifted 100 people to safety
  2. Long term response
    1. exceptional event so less need to act
    2. preventative measures and improvements by Environment Agency, new culvert on the River Jordan extending a further 80m to the River Valency
    3. discussions concerning flood risk management in Upper Valency catchment are, no conclusions yet
Hard engineering water management scheme- 3 gorges dam China
1. Flooding a major problem- particularly in lower parts of the Yangtze in the areaof Sandoupingzhen. Dense population and rich cities made floods more deadly and costly
2. Advantages
  1. Social and economic
    1. tourist attraction
    2. improved navigation and trade as far as Chongqing- Chongqing now one of the fastest growing cities in the world
    3. water in reservoir used for drinking and farming
    4. Jobs created during building and now permanent jobs operating and maintaining
    5. created sense of national pride (largest dam in the world)
  2. Environmental
    1. produces clean renewable hydroelectric energy. Initially thought to meet 10% of China's energy needs, however figure fell as China developed
    2. amount of flooding reduced downstream of the dam
3. Disadvantages
  1. Social and economic
    1. 1.3 mil people had to be relocated as the reservoir flooded
    2. archaelogical sites were covered in water
    3. farmland downstream of the dam became less fertile
  2. Environmental
    1. Yangtze freshwater dolphin became extinct due to increased river traffic and pollution
    2. the sturgeon and alligator are severely threatened because of pollution and disruption to breeding patterns
    3. Dam is built near a fault line so is vulnerable to earthquakes
4. Future
  1. Long term management needed- costly
  2. vital and important tourist attraction- brings in lots of revenue

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Water on the land case studies

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	Creado por georgie.proctor hace más de 10 años