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
• backshore - the area between the high water mark and the landward limit of marine activity
• foreshore - the area lying between the high water mark and the low water mark
• inshore - the area between the low water mark and the point where waves cease to have any influence on the land beneath them
• offshore - the area beyond the point where waves cease to impact upon the sea bed and in which activity is limited to deposition of sediments
• nearshore - the area extending seaward from the high water mark to the area where waves begin to break. Includes;

  • swash zone
  • surf zone
  • breaker zone