Costal transportation

• What is the process called that moves eroded material along the coast?

  Longshore drift
• How do waves typically approach the coast?

  At an oblique angle
• What happens to material when waves hit the coast?

  It is carried up the beach
• What does backwash do to the material on the beach?

  It carries material down at right angles
• What is the overall movement of material along the coast due to waves?

  It zigzags along the coast
• What are the four processes of transportation in coastal environments?

  • Traction
  • Saltation
  • Suspension
  • Solution
• What is traction in coastal transportation?

  Large particles are pushed along the seabed
• What type of particles are carried in suspension?

  Small particles like silt and clay
• How are sand-sized particles transported?

  They are bounced along the seabed
• What happens to soluble materials in coastal environments?

  They dissolve in water and are carried along
• What is deposition in coastal processes?

  Dropping of material on the coast
• When does deposition occur?

  When water slows down and can't carry sediment
• What happens to coasts when deposition exceeds erosion?

  Coasts are built up
• What increases deposition on a coast?

  More erosion and transportation of material
• What characterizes low energy waves?

  They carry material but cause little erosion
• What are constructive waves?

  Waves that deposit more material than they erode
• What is the frequency of constructive waves?

  6–8 waves per minute
• How are constructive waves described in terms of shape?

  They are low and long
• What is the swash in wave action?

  The powerful movement carrying material up the coast
• What does the backwash do in constructive waves?

  It is weaker and carries little material back
• How does longshore drift work?

  1. Waves approach at an oblique angle
  2. Material is carried up the beach
  3. Backwash moves material down at right angles
  4. Material zigzags along the coast
• What are the characteristics of constructive waves?

  • Low frequency (6–8 waves/min)
  • Low and long shape
  • Powerful swash
  • Weaker backwash