coasts

• Waves


  Caused by the wind dragging over the surface of the water
• Fetch


  The length of water the wind blows over
• Stronger wind and longer duration


  Longer fetch and larger waves
• Swash


  When waves move up towards the coastline
• Backwash


  When waves move back down into the sea
• Constructive wave


  Has more swash than backwash, building up the beach and depositing material
• Destructive wave


  Has more backwash than swash, destroying the beach and eroding material
• Processes of coastal erosion

  • Hydraulic action
  • Abrasion
  • Attrition
  • Solution
• Headland


  • Hard resistant rock like limestone or granite sticking out into the sea
• Bay


  • Area of softer rock that has been eroded more easily
• Wave cut platform formation

  1. Wave cut notch forms at base of cliff

  2. Land on top becomes unstable and collapses

  3. Wave cut platform is formed
• Arch, stack and stump formation

  1. Wave action creates fault line in hard rock

  2. Cave forms and eventually arch forms

  3. Arch collapses leaving stack

  4. Bottom of stack erodes leaving stump
• Longshore drift


  Waves come into coastline at angle of prevailing wind, swash at 30 degrees, backwash at 90 degrees, moving material along beach
• Spit


  • Deposition of material at end of coastline, forming new land
• Tombolo


  • Longshore drift joins mainland to an island
• Hard engineering methods


  • Sea walls
  • Rock groynes
  • Breakwaters
  • Revetments
  • Rock armour
  • Wooden groynes
• Hard engineering


  Expensive, intrusive on natural environment, may impact tourism
• Soft engineering


  Less effective but works with natural environment
• Doing nothing is a natural process, but interventions in one place may cause problems elsewhere