Coastal Systems and Landscapes 1

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Coasts are natural systems:

Coasts are systems:

  • Inputs - sediment; energy from wind, waves, tides and currents.
  • Outputs - sediment can be transported at sea or deposited further down.
  • Flows/transfers - erosion, weathering, transportation and deposition occur.
  • Stores/components - landforms are stores of sediment.

They're generally in dynamic equilibrium. A change in one input/output often causes negative feedbacks that restore the balance of the system:

Negative feedback - a change in the system that neutralises the effects. E.g. as a beach is eroded, the cliffs behind it are exposed to wave attack. Sediment eroded from the cliffs is deposited on the beach, causing it to grow again.

They also experience positive feedbacks that change the balance of the system, creating a new equilibrium:

Positive feedback - a change in the system that amplifies the effects. E.g. as a beach starts to form, it slows down waves, which can cause more sediment to be deposited, increasing the size of the beach. The new equilibrium is reached when long-term growth of the beach stops.

There are lots of sources of energy in coastal systems:

Wind:

  • Created by air moving from areas of high pressure to low pressure.
  • Storms - pressure gradient is high and so strong winds.
  • Generate powerful waves.

Waves:

  • Created by the wind blowing over the surface of the sea.
  • Fricton gives it's circular motion.
  • Height is…

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