floods Flashcards
What physical things can cause a flood
heavy rainfall, dry ground, impermeable surfaces, overly saturated soil, snowmelt, steep slopes, compact soil.
What human things can cause a flood
dam breaks, climate change, urbanisation, deforestation
Sometimes after heavy ____ or a fast snow melt there may be too much water for the ____ to hold.
rainfall and river
The river will overflow its ____ and flow onto the ____ either side of it.
banks and land
This is called a river ______.
flood
Usually when it rains the water will soak into the ______.
ground
However, if it is unable to soak into the ground it will flow _____ and into the river. This is the most common cause of _________.
downhill and flooding
What are the steps of river flooding
1) heavy rainfalls
2) some water will soak into the ground but some won’t
3) Water runs downhill, over the surface
4) water quickly reaches the river.
5) river level rises
6) the river floods.
What is Urbanisation
When people settle and lay roads and paths, the water cannot flow over these as they are impermeable and runs into the river.
What is deforestation
When trees are cut down, they can no longer intercept water running down, so more water flows into the river.
Will it flood- very dry soil
yes as the water will just run over it as it is impermeable.
Will it flood-steep slopes
yes as the water will come down and will not have time to saturate the soil.
Will it flood- lots of trees
No, as the trees will intercept the water as it runs through woodland.
Will it flood- large cities or towns
Yes, as the concrete is impermeable and water will just run over it.
Will it flood- soft soil
No, as it is permeable and can be saturated by the rainfall.
Will it flood- very wet
Yes, as no more water can soak into the ground.
What social effects do floods have on people.
people rendered homeless, families separated, people having to evacuated, death, injuries, disease, communication.
What economic effects do floods have on people
exchange rates become worse, infrastructure is damaged, less supplies for shops, businesses will get less business.
what environmental effects do floods have
damage to habitats, animals affected, pollution increases, more land slides.
what political effects do floods have on people.
brings water to civilisations, crops are better.
Who is more affected by floods LICs or HICs
LICs
Why are LICs more affected by floods
This is because they do not have enough money to fund flood preventing projects and have more farmland so floods can be profitable
Why are HICs less affected by floods
They have more money to fund flood preventing measures and are not profited buy floods as there are more office jobs.
What does LIC stand for
Low Income country
What does HIC stand for
High income country
What is hard engineering
Hard engineering is the building of artificial structures to combat river flooding. It can be bad for the environment and have a high cost.
What is soft engineering
Soft engineering is when one use nature to combat floods.It is good for the environment and is usually low cost.
Name 3 kinds of soft engineering
wash land, afforestation and wetland restoration.
Name 3 kinds of hard engineering
Embankments, Dams and flood channelisation.
What is an embankment
It is when the sides of a river are raised to make it harder for the water to flood. If the water does overcome the embankment, it has a harder time getting back in. Hard engineering.
What is flood channelisation
It is when he river is widened or deepened to allow more water in, meaning the river needs more water to flood itself. It is bad for the environment as it can disturb habitats. Hard engineering.
What are wash lands
Wash lands are when the land around the river is allowed to soak up the water from the flood and prevent further flooding. It then cannot be built on. Soft engineering.
What is afforestation
Afforestation is when trees are grown around a river to intercept rain water coming down. This is good for the environment, and can be used to grow timber. It is soft engineering.
What are dams
They are massive structures in the upper course of the river which keep water in, but also let water out at a slower rate than it came in. They are very expensive and cause a large lake covering land which would have been dry. They produce green energy and can be a good target for terrorists. Hard engineering.
