Coastal Landscapes and Waves

• What is the coast?

  Where the land meets the sea
• How long is the UK coastline?

  11,100 miles long
• How are waves formed?

  • Waves are formed by the wind blowing over the sea. 
  • Friction with the surface of the water causes ripples to form and these develop into waves. 
  • The distance the wind blows is called the fetch.
  • The longer the fetch the more powerful the waves
• Why are some waves stronger than others?

  1. Windspeed: the faster and stronger, the larger the waves
  2. Wind Duration: the longer the wind blows, the larger the wave
  3. Fetch: the length of water the wind has blown unobstructed
• What is Fetch?

  • The size of a wave depends on its fetch.
  • The fetch of a wave is the distance it travels.
  • The greater the fetch, the larger the wave.

  For example- The South-East coast of the UK 
• Swash definition

  The wave washing up onto the shoreline
• Backwash definition:

  The water from the wave retreats back out to sea 
• Wave break definition:


  When the water at the top of the wave flows over the water at the bottom, causing the wave to spill over 
• Why do waves break?

  1. Waves start out at sea and have a circular orbit 
  2. As waves approach the shore, friction slows the base of the wave
  3. This causes the orbit to become elliptical
  4. The sea bed is rough and acts as a source of friction
  5. Until the top of the wave breaks over
  6. Water swashes up the beach
  7. Water from a previous wave returns to the sea as backwash

  
• What are the two types of waves at the coast?

  Constructive and destructive
• Characteristics of a destructive wave:

  Destructive wave: waves which remove material from the beach (erodes)

  • Formed in stormy weather
  • Short wavelength
  • High wave height
  • Erodes the coast
  • Weak swash
  • Strong backwash

  
• Describe the characteristics of a constructive wave

  Constructive wave: waves which build up sediment on the coast (deposits)

  • Formed in calm weather
  • Long wavelength
  • Low wave height
  • Build up the coast
  • Strong swash
  • Weak backwash