Causes of river flooding
- Created by: Annis
- Created on: 27-02-14 18:48
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- Causes of river flooding
- Physical (Natural)
- Prolonged rainfall
- Lots of rain causes soil to become saturated, so further rainfall cannot infiltrate (be absorbed)
- This increases surface run off into the river
- This means there is a fast discharge increase in the river
- This increases surface run off into the river
- Lots of rain causes soil to become saturated, so further rainfall cannot infiltrate (be absorbed)
- Snowmelt
- When snow melts lots of water is released quickly
- This causes a fast increase in river discharge
- When snow melts lots of water is released quickly
- Land relief (gradient)
- In a steep sided valley the water will flow down to the river much quicker
- This increases river discharge
- In a steep sided valley the water will flow down to the river much quicker
- The geology of the area
- If the rocks in the surrounding area are impermeable water cannot infiltrate
- This increases the surface run off
- And causes a fast increase in discharge
- This increases the surface run off
- If the rocks in the surrounding area are impermeable water cannot infiltrate
- Prolonged rainfall
- Human
- Deforestation
- Trees are cut down
- They cannot intercept rainfall
- They cannot store/drink water with their roots
- This means the volume of water reaching the river is increased
- They cannot intercept rainfall
- This means the volume of water reaching the river is increased
- This also means there is nothing holding the soil together
- The soil is eroded and washes into the river
- This raises the riverbed and decreases the amount of water the river can hold.
- The soil is eroded and washes into the river
- Trees are cut down
- Urbanisation
- Buildings/roads made of impermeable materials
- Water cannot infiltrate/percolate
- High surface run off
- Water cannot infiltrate/percolate
- Drainage systems
- Water cannot infiltrate/percolate
- High surface run off
- Water cannot infiltrate/percolate
- Buildings/roads made of impermeable materials
- Deforestation
- Physical (Natural)
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