Intro to coastal systems and landscapes

• inputs - marine: waves and tides

  atmospheric: solar energy and weather

  land: rock type and structure and tectonic activity

  people: sea defences, humans, economics and tourism
• processes: weathering and mass movement: freeze-thaw, salt weathering and carbonation

  erosion: abrasion and hydraulic action

  transportation/deposition: long shore drift and solution
• outputs:

  erosional landforms: cliff, spits, stacks and wave cut platform

  depositional landforms: swamps, beach, marsh and sand dune
• Dynamic equilibrium is affected by:

  • sand supply
  • waves
  • sea level
  • location of shoreline
  • storms
• Dynamic equilibrium:

  1. constructive waves build up the beach making it steeper
  2. encourages formation of destructive waves that plunge
  3. redistribution of sediment offshore reduced the beach gradient and makes the wave increase constructive
  4. this is a constant dynamic equilibrium between the wave type and angle of beach
• Negative feedback:

  1. sediment is eroded off the beach during a storm
  2. sediment is deposited offshore forming an offshore bar
  3. waves are now formed to break before reaching the coast. This reduces further erosion at the beach
  4. when the storm calms normal wave conditions rework the sediment from the bar back to the beach
• negative feedback

  • beach is eroded, cliffs behind exposed to wave attack, sediment eroded from cliff is deposited on beach causing it to grow in size