The 3 key processes
happen in a coastal
zone are...
Deposition
when the sea loses energy, it drops the sediment that it has been
carrying, depositing them.
Deposition occurs when...
waves enter shallow water
waves enter a sheltered bay
There are calm conditions with little wind
Transportation
The movement of eroded material up
and down, and along the coast.
Erosion
Erosion usually occurs when the sea takes lots of
energy from the power of destructive waves.
4 things effect erosion...
The shape of the coastline
Headlands of a coastline are exposed to the full force of destructive
waves. Bays are more sheltered from the wave energy because of
wave refraction, so erosion is slower.
Rock Type
Chalks and limestone can form steep cliffs, whereas clay and
softer rock form large bays.
Rock Structure
a discordant coastline, where rocks are at an angle to the
edge of the coastline, will erode at different rates.
The type of wave
The type of wave - the amount of energy a
wave has helps determine the rate of
erosion.
Importance of waves
The power of waves is one of the most important forces that
changes the shape of the coast.
The size of a wave depends on...
How long the wind has been blowing
How strong the wind is
How far the wind has travelled (The fetch)
Waves are created by wind blowing over the surface of the sea.
Wave Types
When a wave breaks, water is washed up the beach. This is
called the swash.
With a constructive wave, the swash is stronger than the
backwash.
If the swash is stronger than the backwash, some of the
sediment carried in the wave will be left behind to build up
the beach. This means that the beach increases in size.
When the water runs back down the beach it is called the
backwash.
With a destructive wave, the backwash is
stronger than the swash.