Factors affecting coastal retreat

• Geology

  • Boulder clay (soft) - 12,000 years old
  • Deposited by glaciers
  • Weak and little resistance to erosion - 5-20 metres high
• Fetch

  • How far the waves have travelled
  • 500-800km across the North Sea
  • Atlantic's fetch is 5000km, causing powerful destructive waves
  • Winter storms in the North Sea are often intense - low pressure rises sea level
  • Deep sea floor - waves are not slowed by friction
• Longshore drift

  • Sediment is easily transported by LSD rather than building up the coastline
  • During high tide there is not enough beach - waves hit base of cliffs
  • Backwash removes more sediment than what is deposited by swash