3.1.3.1 Coasts as Natural Systems

Question 1

What type of system is the Coastal system

Answer 1

Open

Question 2

Sediment Cells

Answer 2

Divided sections of coastline that are self contained for the movement of sediment.

This means that the processes going on in one cell doesn’t affect the system of another.

They are usually divided by headlands.

Question 3

Coastal Inputs

Answer 3

• Marine (waves, tides)
• Atmosphere (sun, wind speed / direction)
• Humans (pollution, defences)

Question 4

Coastal Outputs

Answer 4

• Sediment transfer (erosion and LSD out of system)

- Evaporation

Question 5

Coastal Stores

Answer 5

• Beaches
• Spits
• Bars and Tombolos
• Headlands and Bays
• Cliffs, etc

Question 6

Coastal Flows / Transfers

Answer 6

• Mass-movement processes
• Longshore drift
• Weathering
• Erosion
• Transportation
• Deposition

Question 7

Dynamic Equilibrium

Answer 7

Coastal systems are generally in dynamic equilibrium which is where there is a balance between the inputs and outputs. A change in one often causes negative feedback that restores the equilibrium of the system. However positive feedback does also occur and this creates a new equilibrium.

Question 8

Positive feedback loop in coasts

Answer 8

A storm causes more erosion then usual

The ridge of a sand dune is breached

The ridge is then undercut by wind erosion

This breaks up the dune making it more likely to be eroded

Question 9

Negative feedback coasts

Answer 9

Sediment is eroded from the beach during a storm

Sediment is deposited offshore forming an offshore bar

Waves now break before reaching the beach, dissipating their energy and reducing further erosion when they reach the beach

When the storm calms normal wave conditions rework sediments from the offshore bar back to the beach

The beach is in dynamic equilibrium