Coasts

• waves are caused by the wind
• features of constructive waves


  strong swash, weak backswash, long wavelength, gently sloping wave
• features of destructive waves


  strong backswash, weak swash, small wavelength, steep wave
• the top of the wave is called the crest
• the bottom of the wave is called the trough
• Prevailing wind determines the direction of swash
• what is fetch


  the area which the prevailing wind blows over
• waves slow down on the coast when making contact with the beach
• water running up the beach is called swash
• water running back down to the sea is called backswash
• constructive deposit more than they erode while destructive erodes more than they deposit
• distance between two waves is called wavelength
• what affects rate of erosion

  Geology, width of beach, how exposed the beach is, power of the waves
• types of erosion

  hydraulic action, abrasion, attrition, solution
• longshore drift is a strong process of transportation that follows the direction of the prevailing wind
• longshore drift moves in a zig-zag pattern
• groynes which are made from wood usually can stop longshore drift
• the sea can wash sediment around or over the groyne
• waves deposit sediment when they lose their energy
• Hard engineering in coast


  • Groynes
  • Rock armour
  • Sea wall
• Soft engineering in coasts


  • Beach nourishment
  • Managed retreat
• Rock armour


  Pros - breaks down energy of waves which reduces erosion

  Cons - Expensive , ugly
• Sea wall


  Pros - has a curved surface which reflects waves energy decreasing erosion

  Cons - expensive
• Beach nourishment

  Pros - creates nice looking beaches which attracts visitors

  Cons - High maintenance, nourishment is noisy for locals
• Managed retreat


  Pros - costs nothing

  Cons - loss of land , people forced to relocate
• erosional landforms in a coast

  Wave cut platform

  Headlands and bays
• Transportation and deposition landforms 


  Spits

  Bars