Floods Flashcards
What are floods?
A flood is when a river bursts its banks and overflows.
Name some human causes of flooding.
Building on the floodplain
Clearing vegetation from the valley
River Jordan passes through 100m of underground.
Name some physical causes of flooding.
Steep valley sides
Small drainage basin
Confluence
Low drainage density.
Name some effects of flooding.
For repairs, some shops could be closed for a long time.
Homeowners could be terrified by the experience, loss of possessions, they might be homeless until their houses are repaired.
Loss of community resources and facilities.
For tourists, loss of possessions, holiday interrupted, less likely to return.
Homes could be inhabitable for a while
businesses destroyed/damaged
cars carried away
Repair could be expensive.
Explain how you would reduce the water in a river.
Build a dam across the river which will trap water and stores in it a reservoir, the water can then be released in a controlled way. They can also be used to generate electricity as water turns a turbine as it passes through. Hydro electric power (HEP)
However dams are very expensive and land is flooded by the reservoir.
If you plant moor trees in the drainage basin they will intercept more water through their roots. This reduces the amount of water getting to the river.
However to plant trees land normally used for farming is needed. Trees take many years to grow, especially deciduous trees, which intercept the most water.
Give 4 ways to prevent a flood from happening.
Reduce the amount of water in the river Increase the capacity of the river Speed the flow of water in the river Alternative solutions: Allow flooding Overflow channels
How do you increase the capacity of a river?
Widen the river by digging out a larger channel.
However wildlife will lose habitats as work is carried out on the banks.
Deepen it by digging out the channel.
However wildlife will lose wildlife as work is carried out.
How do you speed the flow of water in the river?
Straighten the river, this speeds the flow of water to sea.
Concrete ban’s are smoother than natural banks and therefore water moves more quickly to see.
What are the alternate solutions?
When the water level rises, floodgates may be opened and the water channeled out to sea or into temporary stage lakes.
Allow flooding.
How do you speed the flow of water in the river?
Straighten the river, this speeds the flow of water to sea.
Concrete ban’s are smoother than natural banks and therefore water moves more quickly to see.
