Coasts

• What areas of the coast are allowed to erode and flood naturally?


  Areas considered to be of low value, such as those not used for housing or farmland
• What is one advantage of allowing coastal areas to erode and flood naturally?


  It encourages the development of beaches
• What is a disadvantage of building curved sea walls?


  They reflect wave energy back to the sea, keeping waves powerful
• What is a disadvantage of maintaining sea walls?


  The cost of maintenance is high
• What are the pros and cons of building groynes?


  Advantages:

  • Prevents movement of beach material by longshore drift
  • Allows beach build-up, providing natural defense and tourist attraction

  
  

  Disadvantages:

  • Can be seen as unattractive
  • Costly to build and maintain
• What are the pros and cons of using rock armour or boulder barriers?


  Advantages:

  • Absorbs wave energy
  • Allows beach build-up

  
  

  Disadvantages:

  • Expensive to obtain and transport boulders
• What is beach nourishment and its advantages?


  • Replaces beach or cliff material lost to erosion
  • Natural defense against erosion and flooding
  • Attracts tourists
  • Relatively inexpensive but requires constant maintenance
• What is managed retreat in coastal management?


  Allowing areas of the coast to erode and flood naturally, usually in low-value areas
• What are the advantages of managed retreat?


  Encourages natural beach and salt marsh development and is low cost
• Who funds the Flood Action Plan?

  The World Bank
• What are some sustainable ways to reduce flooding?

  Building coastal flood shelters on stilts and implementing early warning systems
• What are the economic and social impacts of flooding in London and the Thames Estuary?


  Economic impacts:

  • Billions to rebuild infrastructure
  • Loss of jobs due to business destruction

  
  

  Social impacts:

  • Death and injury to millions
  • Loss of homes
• What are other impacts of flooding in London and the Thames Estuary?


  • Destruction of historical buildings (e.g., St Paul’s Cathedral)
  • Destruction of animal habitats
  • Pollution of the river
  • Destruction of schools, hospitals, and transport
• What causes sea level rise?

  Global warming causing polar ice caps to melt
• What areas of England are particularly at risk of flooding due to rising sea levels?


  Especially the south west, including London
• What are the types of hard engineering in coastal management?


  • Sea wall
  • Groynes
  • Rock armour
• What was the coastal management scheme introduced in Mappleton in 1991?


  A £2 million scheme involving rock armour and two rock groynes
• What was the outcome of the coastal management scheme in Mappleton?


  Mappleton and the cliffs are no longer at great risk from erosion
• What is a negative effect of the coastal management scheme in Mappleton?


  Increased erosion south of Mappleton
• What are the characteristics of Bangladesh as an LEDC vulnerable to flooding?


  • Densely populated
  • Delta formed by Ganges, Brahmaputra, and Meghna rivers
  • 25% of land is less than 1 metre above sea level
  • Annual flooding due to rivers bursting their banks
• What are the processes of cliff erosion?


  1. Weather weakens the top of the cliff
  2. Chemical weathering: weak acids dissolve rocks
  3. Physical weathering: temperature and water cause cracks
  4. Biological weathering: living organisms break up rocks
• What are the types of mass movement in coastal processes?


  • Rock fall
  • Landslide
  • Cliff collapse
  • Mudflow
  • Rotational slip
• What are the types of coastal erosion processes?

  1. Hydraulic action
  2. Abrasion
  3. Attrition
  4. Solution
• What is hydraulic action in coastal erosion?


  Air trapped in joints and cracks is compressed by breaking waves, weakening the cliff
• What is abrasion in coastal erosion?


  Bits of rock and sand grind down surfaces like sandpaper
• What is attrition in coastal erosion?


  Waves smash rocks and pebbles together, breaking them and making them smoother
• What is solution in coastal erosion?


  Acids in seawater dissolve certain types of rock, such as chalk or limestone
• How are waves formed?


  Waves are caused by friction between wind and water
• What factors influence the size and energy of a wave?

  Wind duration, wind strength, and fetch
• What are the characteristics of destructive waves?


  • Created from strong storms
  • High energy and long fetch
  • Tend to erode the coast
  • Stronger backwash than swash
  • Short wavelength, high and steep
• What are the characteristics of constructive waves?


  • Created in calm weather
  • Less powerful than destructive waves
  • Break on shore and deposit material
  • Stronger swash than backwash
  • Long wavelength, low in height
• What is weathering in coastal processes?


  • Breakdown of rocks and surface materials by atmospheric actions
  • Weakens rocks, making them more susceptible to erosion and mass movement
• What are the types of weathering?

  1. Chemical
  2. Physical
  3. Biological
• What is chemical weathering?


  Weak acids dissolve minerals in rocks
• What is physical weathering?


  Caused by temperature changes and water, leading to cracks in rocks
• What is biological weathering?


  Rocks are broken up by living organisms, such as burrowing animals
• What are the types of coastal processes related to mass movement?


  • Rock fall
  • Landslide
  • Cliff collapse
  • Mudflow
  • Rotational slip
• What is the process of rock fall?


  • Occurs when rocks break loose from a cliff and fall to the ground
• What is a landslide?


  • The sudden and fast movement of rock and soil down a slope
• What is cliff collapse?


  • The failure of a cliff face due to erosion or weathering