COASTS: The Coastal System

Question 1

Why are coasts considered natural systems?

Answer 1

They have inputs, outputs, flows and stores of sediment and energy.

Question 2

There are 4

What are the inputs of sediment into the coastal system?

Answer 2

• Eroded sediment from rivers and cliffs.
• Crushed shells of marine organisms.
• Offshore deposits transported by waves, tides and currents.
• Sediment from the formation of estuaries from sea levels rising.

Question 3

What are the inputs into the coastal system?

Answer 3

Sediment.

Energy - wind, waves, tides and currents.

Question 4

What are the outputs of coastal systems?

Answer 4

Sediment washing out to sea or being deposited further along the coast.

Question 5

What are the flows/transfers within the coastal system?

Answer 5

Erosion

Weathering

Transportation

Deposition

Question 6

What are the stores/components of the coastal system?

Answer 6

Landforms, eg beaches, dunes and spits.

Question 7

Give an example of negative feedback in the coastal system:

Answer 7

• Beach is eroded.
• Cliffs are exposed to wave attack.
• Sediment eroded is deposited on beach.
• Beach grows in size.

Question 8

Give an example of positive feedback in the coastal system:

Answer 8

• Beach forms.
• Waves slow down.
• More sediment is deposited.
• Beach size increases.

Question 9

What do negative feedbacks do to the system?

Answer 9

Restore the balance of the system.

Question 10

What do positive feedbacks do to the system?

Answer 10

Change the balance of the system.

Create a new equilibrium.

Question 11

What are the sources of energy in the coastal system?

Answer 11

Wind

Waves

Tides

Currents

Question 12

What are winds created by?

Answer 12

Air moving from areas of high pressure to areas of low pressure.

Question 13

What can strong winds generate?

Answer 13

Powerful waves.

Question 14

Prevailing winds

Answer 14

When the wind blows from the same direction.

Question 15

What type of waves do prevailing winds cause?

Answer 15

Higher-energy waves than winds that change direction frequently.

Question 16

What are waves created by?

Answer 16

Wind blowing over the surface of the sea, causing friction and giving the sea a circular motion.

Question 17

The effect of a wave on the shore depends on what?

Answer 17

The height of the wave.

Question 18

What is wave height affected by?

Answer 18

Wind speed

Fetch of the wave

Question 19

Fetch

Answer 19

The maximum distance of sea the wind has blown over in creating the waves.

Question 20

High wind speed and long fetch create what sort of waves?

Answer 20

Higher and more powerful waves.

Question 21

What causes a wave to break as it nears the shore?

Answer 21

• Friction with sea bed slows the bottom of the waves.
• Wave motion becomes more elliptical.
• Crest rises up and collapses.

Question 22

What is the frequency of constructive waves?

Answer 22

6-8 waves per minute

Question 23

What is the frequency of destructive waves?

Answer 23

10-14 waves a minute

Question 24

Describe constructive waves:

Answer 24

• Low frequency
• Low & long
• Elliptical cross profile
• Powerful swash deposits material

Question 25

Describe destructive waves:

Answer 25

* High and steep * Circular cross profile * Higher frequency * Strong backwash removes material from the beach

Question 26

Tides

Answer 26

Periodic rise and fall of the ocean surface caused by the gravitational pull of the Moon and the Sun.

Question 27

What do the tides affect?

Answer 27

The position at which waves break on the beach.

Question 28

Current

Answer 28

The general flow of water in one direction which moves material along the coast. ## Footnote *Can be caused by wind or by variations in water temperature and salinity.*

Question 29

Give the characteristics of high-energy coasts:

Answer 29

* Inputs of energy from large, powerful waves. * Sandy coves * Rocky landforms * Rate of erosion is higher than rate of deposition.

Question 30

Give the characteristics of low-energy coasts:

Answer 30

* Low inputs of energy from small, gentle waes. * Saltmarshes * Tidal mudflats * Rate of deposition is higher than the rate of erosion.

Question 31

Sediment budget

Answer 31

The difference between the amount of sediment that enters the system and the amount that leaves.

Question 32

Positive sediment budget

Answer 32

More sediment enters the system than leaves it and the coastline builds outwards.

Question 33

Negative sediment budget

Question 34

Sediment cells / littoral cells

Answer 34

Lengths of coastline (often between two headlands) that are largely self-contained for the movement of sediment.

Question 35

Are sediment cells open or closed systems?

Question 36

How many sediment cells are there in the UK coastline?

Answer 36

11

Question 37

When the wind blows from the same direction.

Answer 37

Prevailing winds

Question 38

The maximum distance of sea the wind has blown over in creating the waves.

Answer 38

Fetch

Question 39

Periodic rise and fall of the ocean surface caused by the gravitational pull of the Moon and the Sun.

Answer 39

Tides

Question 40

The general flow of water in one direction which moves material along the coast. ## Footnote *Can be caused by wind or by variations in water temperature and salinity.*

Answer 40

Current

Question 41

The difference between the amount of sediment that enters the system and the amount that leaves.

Answer 41

Sediment budget

Question 42

More sediment enters the system than leaves it and the coastline builds outwards.

Answer 42

Positive sediment budget

Answer 43

Negative sediment budget

Question 44

Lengths of coastline (often between two headlands) that are largely self-contained for the movement of sediment.

Answer 44

Sediment cells / littoral cells