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River Flooding - Coggle Diagram
River Flooding
The water cycle
precipitation
collection
ground water
evaporation
transpiration is from trees
condensation
forms clouds
What causes a river to flood (physical)
rapid melting of snow
Leaves lots of water around
very wet soil
saturated ground stops the water sinking into the ground
very dry soil
Tightly packed ground builds up crust leaving water resting on the top
steep slopes
When rain runs down a hill it has little time to soak in so it remains on the surface
Response to floods
government help
emergency supplies
monitor risk of flooding
What causes a river to flood (human)
deforestation
Risk of flood has doubled since tree clearing began why?
Leaves act as an umbrella to stop lots of rain hitting the ground
Roots slow down the movement of water (stops groundwater)
Water on leaves evaporate before the water reaches the ground
Roots take up water and stop the water from reaching a river
Urbanization
Rain falls on new tarmac so the water can't soak in and stays on the surface
Large towns mostly at risky to flooding
Examples of floods
Sussex 2000
Excessive rainfall meant southern England was flooded
Build ing in the floodplain made houses submerged
The ground became saturated
Rivers burst their banks and flooded nearby houses
Bangladesh 2004
monsoon season
deforestation
huge rivers run through the country
Bangladesh is a flat country that is only 6 metres above sea level
How does the water cycle effect flooding
when there is a lot of rainfall the ground becomes saturated meaning it can't take up any more water so the water has to rest on top