water on the land

Features of a river basin.
1. Confluence
  1. Where two rivers meet
2. Tributary
  1. Small river or stream that joins a larger one
3. Mouth
  1. Where the river meets the sea
4. Watershed
  1. The boundary between one drainage basin and another
5. Drainage Basin
  1. The area drained by a river & its tributaries
6. Source
  1. The start of the river, often a spring or a lake
What causes flooding?
1. Physical
  1. heavy rainfall over a long period of time
  2. heavy snowfall
  3. area laying in impermeable rock (water cant drain away)
2. Human
  1. deforestation
  2. building concrete structures(doesn't allow water to drain)
Tewkesbury floods 2007 England
1. Facts
  1. 80;90 cm of heavy rain fell in one day (equivalent to nearly two months rainfall)
2. Effects
  1. 3 people died
  2. thousands of homes flooded
  3. £25 million damage to roads
  4. water treatment flooded and shut down- no drinking water
  5. electricity station also flooded- no electricity
3. responses
  1. 50 million bottles of water distributed
  2. people evacuated from homes
  3. long term- flood defences installed to water treatment and power station
River management strategies
1. Hard engineering- man made strategies to prevent flooding
  1. Dams & reservoirs- huge walls that block river or surround river. Advantage- can easily be controlled and can be used to supply drinking water. Disadvantage- expensive
  2. Channel straightening- build artificial channel. Advantage- river carries water quicker. Disadvantage- more erosion and floods villages further down stream
2. Soft engineering- tries to reduce effects without stopping it
  1. Flood warnings- warnings through tv, radio, web, saying flood is due. Advantage- people have time to move and place sandbags. Disadvantage- people may not get message and doesnt actually stop flood
  2. Flood plain zoning- prevents building on floodplains. Advantage- reduces risks to buildings. Disadvantage- difficult to limit cities and too late for some areas
Three gorges dam, china
1. facts
  1. constructed at river yangtse
  2. reservoir should reduce risk of flooding protecting 15 million people and 25,000 ha farmland
2. environmental issues
  1. water in reservoir becoming heavily polluted from shipping and waste
3. social issues
  1. 1.4 million forced to move to build the dam and reservoir
4. economic issues
  1. cost $25.5 billion
Transportation- when material is carried along
1. solution- material carried in solution
2. traction- largest rocks rolled away
3. saltation- smallest rocks bounced along bed
4. suspension- smallest rocks carried along
Erosion- wearing away the rocks
1. solution- rocks dissolve into water
2. hydraulic action- water forced into cracks
3. attrition-- rocks bounce off each other and break
4. abrasion- scraping away
Bangladesh floods 2004
1. facts
  1. 35 cm rain fell in one day
2. effects
  1. 60% country flooded and 40% capital floodded
  2. 750 deaths
  3. 100,000 people suffering from diarroea
  4. 30 million left homeless
  5. roads, railways, bridges destroyed
  6. $7 billion damage
3. responses
  1. food supplies, clothing, medicines, blankets distributed
  2. water aid supplied water purification tablets
  3. united nations raised money
  4. long term- flood shelters built and embankments built along river

Siguiente

Descripción

Resumen del Recurso

Similar

	Creado por Aimee Shanks hace más de 9 años