Flooding Flashcards
What is the water cycle?
This is the continuos movement of water between the sea, the land and the air.
What is precipitation?
The transfer of water from the air to the land. It may fall as rain, hail, sleet or snow.
Does the amount of water stay the same?
The amount of water in the cycle always stays the same!
Some of the water may be stored in the sea, in the air or on land.
Some of the water will be moved or transferred around the cycle.
What is evaporation?
The transfer and change of water (from the ground) into vapour
What is transpiration?
The transfer as well as the change of water from plants to vapour in the air
What is condensation?
Condensaition is when Vapour in the air changes back into a liquid. It forms small droplets that are visible as cloud.
What is surface water?
The transfer of water back to the sea over the ground surface.
This is called surface runoff and is easiest to see as rivers.
What is ground water?
The movement/transfer of water through the ground back to the sea.
What is the river basin?
The river basin is an area of land where rain collects
What is the source?
The point at where the river begins
What is the mouth?
The mouth is the end of the river where it flows into either a lake or the sea.
What is a channel?
Rivers flow in a channel, they have a bank and a bed
What is watershed?
The highland boundary/edge of the river basin.
What is a tributary?
A small river that flows into the main river
What are six factors that cause flooding?
Rock and soil type: impermeable rocks and soils do not allow rain to soak through them. Any
rain that falls will stay near the surface.
Very wet soil: if rain has been falling for some time, the soil may become full of water. Any
further rain is unable to soak into the ground and remains on the surface.
Very dry soil: soil that is baked hard by the sun in dry weather builds up a crust. Rain is
unable to soak through the crust and so remains on the surface.
Steep slopes: rain falling on a steep slope runs quickly downhill. It has little time to soak into
the ground so most stays on the surface.
Cutting down trees (deforestation)
Many of the world’s forests are being cleared to make way for other developments. In some
countries the number of serious floods has more than doubled since large-scale tree
clearing began.
Buildings and roads (urbanisation)
Rain falling on concrete and tarmac is unable to soak into the ground, so stays on the
surface. Gutters and drains then carry the water quickly and directly to the river. Large
towns are most at risk.