Sec 3 NA Coastal Protection Measures

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  • 1. Coastal Protection Measures
  • 2. Different types of engineering
    • Hard engineering
    • Soft engineering
  • 3. Hard engineering
    • Seawalls
      • Is usually made of concrete which absorbs the energy of the wave
      • Protect the coast against strong waves especially during storms
  • 4.  
  • 5.  
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  • 8. Hard engineering
    • Breakwaters
      • Usually made of granite.
      • Creates a zone of shallow water between itself and the coast so that waves will break against it before reaching the coast.
  • 9.  
  • 10.  
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  • 13. Hard engineering
    • Groynes
      • Is a low wall built at right angles to prevent materials from being transported away by the longshore drift.
      • This enables the transported materials to accumulate on the side of the groyne facing the longshore drift.
  • 14.  
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  • 16. Hard engineering
    • Gabions
      • Are used to protect river banks against erosion.
      • Similarly, these wire cages containing small rocks are used to form a wall to protect other coastal protection structures such as seawalls.
  • 17.  
  • 18.  
  • 19. Soft engineering
    • Stabilising coastal dunes
      • The dunes form as a result of the vegetation trapping and stabilising the sand.
      • The dunes extend several kilometres inland and to height of more than 100 metres.
      • Plant vegetation to trap and bind the sand together, preventing sand from being blown away.
  • 20.  
  • 21.  
  • 22. Soft engineering
    • Planting mangroves along the shore
      • Mangrove trees have prop roots or kneed roots that anchor the trees firmly in the muddy soil.
      • These roots also bind the loose soil and protect it from erosion.
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  • 26. Soft engineering
    • Beach nourishment
      • This involve adding large amounts of sand to a beach that is being eroded.
      • Longshore drift removes the sand from the beach and carries it further down the coast.
      • People will bring in sand from other areas and deposit the sand onto the beach again.
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  • 31. Soft engineering
    • Encourage growth of coral reefs
      • Coral reefs are masses of rock like substance called corals growing in shallow water.
      • They protect beaches against coastal erosion by reducing the speed of the waves approaching the coast.
      • Resulting the waves losing most of their energy.
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  • 35. Coastal Protection Management Comparison of the Effectiveness of Coastal Management Protection Measures – Hard Engineering Gabions Groynes Breakwaters Seawalls Disadvantages Advantages
  • 36. Coastal Protection Management Comparison of the Effectiveness of Coastal Management Protection Measures – Hard Engineering
    • Need regular maintenance
    • Weaken wave energy
    • Reduce coastal erosion
    Gabions
    • Erosion on parts of coast not protected by groynes
    • Protect coast from high energy waves
    • Encourage build-up of beach
    Groynes
    • Erosion on parts of coast not protected by breakwaters
    • Protect coast from high energy waves
    • Encourage build-up of beach
    Breakwaters
    • Erosion may lead to collapse of seawall
    • Costly
    • Absorb shock of waves
    • Reduce erosion of shore
    Seawalls Disadvantages Advantages
  • 37. Coastal Protection Management Comparison of the Effectiveness of Coastal Management Protection Measures – Soft Engineering
    • Can affect the depth of coasts – implications for port activities/coastal transportation
    • Helps trap sediments to form islands
    • Prevents coastal erosion
    Planting of mangroves
    • Affects investment opportunities in coastal areas
    • Allows nature to take its course
    • Avoids loss of lives and properties
    Relocation properties
    • Expensive
    • Affects marine ecosystem
    • Requires constant supply of new sand
    • Improves beach quality
    • Improves storm protection
    Beach nourishment Disadvantages Advantages
  • 38. Coastal Protection Management Comparison of the Effectiveness of Coastal Management Protection Measures – Soft Engineering -
    • Reduces wave energy
    • Encourages the growth of living organisms
    • Improves fishing opportunities
    Growth of coral reefs
    • Dunes are easily eroded if vegetation is not present
    • Vegetation growing on dunes anchor sand
    • Protects coast from sea
    Stabilizing dunes Disadvantages Advantages