Coasts are shaped by the sea and the action of waves. Waves act in different ways, through the processes of erosion, transportation and deposition.
A coast is found where the land meets the sea. Coasts undergo change due to coastal processes and (as with rivers) there are main processes at work:
Each of these processes involves the power of the sea and the effect of waves that are carried to shore. However other factors also change and shape our coast.
Factors which change and shape our coast
Human activity and land use:
The way in which humans manage and use coastal areas helps shape the coast. Some areas of coast are valued more than others. This will influence the way coasts are used and managed.
List two ways in which humans use the coast
Weather and climate
The weather and climate of coastal areas can contribute to the process of erosion and weathering.
Provide examples of the ways in which weather conditions affect the coastal zone.
Geology the geology and rock types found in coastal areas influence how coastal processes work ie hard rock resists erosion
The power of waves is one of the most significant forces of coastal change. Waves are created by wind blowing over the surface of the sea. As the wind blows over the surface of the sea, friction is created, producing a swell in the water. The energy of the wind causes water particles to rotate inside the swell. This moves the wave forward. The size and energy of a wave is influenced by:
The length of time the wind has been blowing
The strength of the wind
How far the wave has travelled (called the fetch)
Longshore drift is the result of the movement of water along the beach as a result of the angle broken waves ‘hit’ the coast. As the water moves down the beach it carries sand and other materials. Another name for longshore drift is a current.
A wave develops due to the action of wind.