Waves and wave types

When the wind blows over the sea, it creates waves. The size and energy of the wave depends on certain factors:

the - how far the wave has travelled
the strength of the wind
how long the wind has been blowing for

Long fetch (up to 8,000 km) - South-westerly wind will produce large powerful waves. Short fetch (less than 200 km) - South-easterly wind will produce small waves.

Wave types

There are two different types of waves - and . They can affect the coastline in different ways. When a wave reaches the shore, the water that rushes up the beach is known as the . The water that flows back towards the sea is known as the . The energy of the swash and backwash determine the type of wave.

Destructive waves

Constructive waves are high in proportion to their length. They have a weak swash but a strong backwash. A tall breaker is a tall wave which breaks downwards with great force.

The characteristics of a destructive wave are:

weak swash and strong backwash
occurs in stormy conditions, with strong winds
the strong backwash removes from the beach
the waves are steep and close together
tall waves with short wavelength
they arrive quickly and have a high frequency – a lot of them come in a short period of time

Constructive waves

Destructive waves are low in proportion to their height. They have a strong swash and weak backwash.

The characteristics of a constructive wave are:

small waves, with low wave height and long wavelength
occurs in calm conditions, without much wind
strong swash and weak backwash
the strong swash brings sediments to build up the beach
the backwash is not strong enough to remove the sediment
the waves are low and further apart

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Coastal processes - EdexcelWaves and wave types