Coasts

• How are waves formed?

  Waves are formed when wind blows over the sea or ocean, causing friction.
• What effect does stronger wind have on wave formation?


  Stronger wind increases friction and creates bigger waves.
• What is the fetch in relation to wave formation?


  The fetch is the distance over which the wind can affect the ocean.
• Why do waves break as they approach shallow areas?

  Waves break because the base slows down due to friction with the seabed.
• What happens to the wave height and wavelength as waves approach the shore?


  Wave height increases and wavelength decreases as waves approach the shore.
• What is the motion of water particles in a wave?


  Water particles move in a circular motion within a wave.
• What does the energy in a wave do?


  Energy moves forward in a wave, not the water particles.
• What factors affect the height and strength of waves?

  • Speed of the wind
  • Duration of wind blowing
  • Distance over which the wind has traveled (fetch)
• What are spilling waves and when do they occur?


  Spilling waves occur in summer and are small with long wavelengths and low amplitudes.
• How do spilling waves affect the beach?


  Spilling waves build up the beach by depositing sand.
• What is the swash and backwash of spilling waves?


  Spilling waves have a strong swash that transports sand up the beach.
• What are constructive waves?


  Constructive waves are those that build up the beach by depositing sand.
• What are plunging waves and when do they occur?


  Plunging waves occur in winter and are taller with shorter wavelengths.
• How do plunging waves affect the beach?


  Plunging waves erode the beach by removing sand.
• What is the effect of plunging waves on beach profile?


  Plunging waves create a steep beach profile.
• What is a rip current?


  A rip current is a flow that occurs when backwash flows under an incoming wave.
• Why are plunging waves considered dangerous?


  Plunging waves are dangerous because they arrive quickly and can create strong rip currents.
• What are destructive waves?

  Destructive waves are those that erode the beach by removing sand.
• Compare spilling waves and plunging waves in terms of their characteristics and effects on the beach.

  **Spilling Waves:**

  • Occur in summer
  • Small, long wavelengths, low amplitudes
  • Strong swash, builds up beach

  
  

  **Plunging Waves:**

  • Occur in winter
  • Taller, shorter wavelengths, larger amplitudes
  • Strong backwash, erodes beach
• What are the two main categories of coastal defenses mentioned?

  Hard and Soft Engineering
• What are the types of hard engineering coastal defenses listed?

  • Groynes
  • Gabions
  • Rock Armour
  • Sea Walls
• What materials are groynes usually made of?

  Wood
• What is the primary function of groynes?

  To prevent longshore drift
• How do groynes affect sediment?

  They cause sediment to build up, creating a beach
• What are the advantages and disadvantages of using groynes?

  Advantages:

  • Breaks wind for tourists
  • Doesn’t impede access to the beach
  • Builds up a sandy beach
  • Cheap (5000/yr)
  • Long lasting

  
  

  Disadvantages:

  • Dangerous for children
  • Ugly
  • Ineffective during storms
  • Damages coast further down
  • Impedes access across the beach
• What is rock armour used for?

  To provide a buffer against erosion
• What are the advantages and disadvantages of rock armour?

  Advantages:

  • Slows down backwash
  • Doesn’t disrupt transportation processes
  • Doesn’t impede access along the beach
  • Versatile
  • Lasts long

  
  

  Disadvantages:

  • Ugly
  • Impedes access to the beach
  • Dangerous
  • Expensive
  • Quarrying is bad for the environment
• What is the purpose of a recurved sea wall?

  To prevent waves from reaching economically beneficial areas
• What are the advantages and disadvantages of recurved sea walls?

  Advantages:

  • Provides a sense of safety
  • Attracts tourists
  • Long lasting
  • Doesn’t impede access along the beach
  • Works well with high wave energy

  
  

  Disadvantages:

  • Ugly
  • Destroys animal habitats
  • Expensive
  • Impedes access to the beach
  • Not useful when waves overtop
• What are gabions made of?

  Rocks in mesh netting
• What are the advantages and disadvantages of gabions?

  Advantages:

  • Cheap
  • Not as ugly
  • Doesn’t impede access across the beach
  • Increases percolation
  • Absorbs energy from waves

  
  

  Disadvantages:

  • Impedes access to the beach
  • Dangerous when damaged
• What are the types of soft engineering coastal defenses mentioned?

  • Beach Nourishment
  • Beach Reprofiling
  • Dune Regeneration
  • Coastal Retreat
• What is beach nourishment?

  Adding sand and shingle to the beach
• What are the advantages and disadvantages of beach nourishment?

  Advantages:

  • Looks pretty
  • Cheap

  
  

  Disadvantages:

  • Requires beach closure
  • Needs frequent maintenance
  • Offshore dredging can increase erosion
• What is beach reprofiling?

  Taking sand from lower down the beach to fill eroded areas
• What are the advantages and disadvantages of beach reprofiling?

  Advantages:

  • Reduces wave energy
  • Looks pretty

  
  

  Disadvantages:

  • Causes problems further down
  • Requires beach closure
  • Only effective in low wave energy conditions
• What is dune regeneration?

  Efforts to create dunes by planting obstacles and vegetation
• What are the advantages and disadvantages of dune regeneration?

  Advantages:

  • Helps ecosystems
  • Increases biodiversity
  • Cheap
  • Looks pretty

  
  

  Disadvantages:

  • Requires beach closure
  • Takes a long time
  • Storm waves can damage the process
• What is coastal retreat?

  Allowing low economic value areas to be flooded
• What are the advantages and disadvantages of coastal retreat?

  Advantages:

  • Good for the natural environment
  • Encourages sand dune and marsh formation

  
  

  Disadvantages:

  • Requires compensation