Coasts Specification


1.1: What is a coastal system and what are the dynamics of coastal environments?

The coastal system is one of inputs and outputs. There are 2 systems:

  • The cliff system with inputs compromising the sub-aerial processes of weathering and the atmospheric processes of wind erosion; a throughput compromising cliff mass movement of falls, slips and slumps; and an output of sediment at the base of the cliff DEPOSITED( or trasnported by marine processes.
  • The beach system with an input of sediment from longshore drift (LSD), the cliff and offshore, a throughput of LSD and an output of LSD and destrive WAVES( carrying sediment offshore.

Sediment Cells:

  • Areas of coasts are usually defined by headlands (a narrow piece of land that projects from a coastline into the sea) and bays (a broad inlet of the sea where the land curves inwards) in which marine processes are largely confined.

Dynamic Equilibrium:

  • This is acheived when inputs = outputs. The relationship constantly changes due to erosion, transport and deposition.

Constructive and Destructive waves:


  • 6-8 waves per minute.
  • Swash is stronger than backwash.
  • They create, low flat and gentle waves.
  • Form beach ridges and berms.


  • 10-14 waves per minute.
  • Backwash is stronger than swash.
  • Combs down material to create a var.
  • High, steep waves.

Most beaches experience the alternating action of


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