The Coastal System

Question 1

True or false? Coasts are a natural system

Answer 1

True

Question 2

What are sediment stores on coasts?

Answer 2

Depositional landforms are stores of sediment.

Question 3

What are the flows/transfers of sediments on coasts?

Answer 3

Processes such as erosion, weathering, transportation and deposition move sediment within a system

Question 4

What are the energy inputs on coasts?

Answer 4

• wind
• waves
• tides
• currents

Question 5

Coastal system aren’t normally in dynamic equilibrium. True or false?

Answer 5

False. They are normally in dynamic equilibrium.

Question 6

What restores the balance in a system if a change in an output or input occurs?

Answer 6

Negative feedbacks

Question 7

Give an example a negative feedback in a coastal system.

Answer 7

As a beach is eroded cliffs are exposed to wave attack. Sediment eroded from cliffs is then deposited and builds the beach up again.

Question 8

Give an example of a positive feedback in a coastal system.

Answer 8

As a beach starts to form it slows waves down, causing more deposition, increasing beach size

Question 9

What are positive feedbacks?

Answer 9

When a change in the system causes amplification of effects.

Question 10

How is wind created?

Answer 10

By air moving from areas of high pressure to areas of low pressure.

Question 11

Describe the pressure gradient and therefore wind strength in storms.

Answer 11

Very high making winds very strong

Question 12

What is prevailing wind?

Answer 12

Wind that blows from the same direction

Question 13

Prevailing wind generates higher energy waves than winds that change direction. True or false?

Answer 13

True.

Question 14

How are waves formed?

Answer 14

Wind blowing over the sea’s surface causes friction between the wind and surface, creating a circular motion in the water

Question 15

What are the higher and lower levels of a wave called ?

Answer 15

Wave crest and trough respectively.

Question 16

How do you work out a wave’s wavelength?

Answer 16

The distance between two wave crests.

Question 17

How does a wave break?

Answer 17

As the beach gets shallower friction occurs and causes the circular motion to topple, causing it to crash.

Question 18

What is a wave’s fetch?

Answer 18

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

Question 19

What effects a wave’s height?

Answer 19

Wind speed and fetch.

Question 20

What are the two wave types?

Answer 20

Constructive and destructive.

Question 21

What are the characteristics of a constructive waves?

Answer 21

• low frequency (6-8 per minute)
• low and long wave
• strong swash
• weak backwash

Question 22

What are the characteristics of a destructive wave?

Answer 22

• higher frequency (10-14 per minute)
• high and steep
• weak swash
• strong backwash

Question 23

What are tides?

Answer 23

The periodic rise and fall of the ocean surface

Question 24

What are tides caused by?

Answer 24

The gravitational pull of the moon and sun

Question 25

Describe how tides affect waves.

Answer 25

The position at which waves break on the beach

Question 26

Where are most landforms created and destroyed on a beach?

Answer 26

The area of land between maximum high tide and minimum low tide

Question 27

Define current

Answer 27

Current is the general flow of water in one direction

Question 28

What causes currents

Answer 28

Caused by wind OR variations in water temp. and salinity

Question 29

True or false. Currents do not move material along the coast

Answer 29

False, they do

Question 30

High energy coasts receive high inputs of energy in the form of large, powerful waves. What 3 things are they caused by?

Answer 30

* strong winds * long fetch * steep offshore zones

Question 31

Characterise the landforms on a high energy coast.

Answer 31

Sandy coves | And rocky landforms (eg caves, stacks and arches)

Question 32

On a high energy coast what is the relationship between erosion and deposition?

Answer 32

Erosion rate > deposition rate

Question 33

On a low energy coast what is the relationship between erosion and deposition?

Answer 33

Deposition rate > erosion rate

Question 34

What landforms night you commonly find on a low energy coast?

Answer 34

Salt marshes and tidal mudflats

Question 35

What are the 4 potential causes of low energy inputs on a low energy coast?

Answer 35

* gentle winds * short fetch * gently sloping offshore zones * offshore obstacles like islands or reefs, slowing waves down

Question 36

What are low energy coast waves like?

Answer 36

Small and gentle

Question 37

How can sea level rise create a source of sediment on a coast?

Answer 37

It can flood river valleys, forming estuaries, their sediment becomes part of the coastal system

Question 38

Name the 3 sediment sources (inputs) to a coast (vary your answer)

Answer 38

* rivers bringing sediment from Inland * sea level rise ( explained in other card) * sediment eroded from cliffs * crushed shells of marine life * waves, tides & currents transporting sediment from offshore deposits

Question 39

Define sediment budget

Answer 39

Difference between amount of sediment inputs and amount of sediment outputs

Question 40

Describe what happens if a coast has a positive sediment budget

Answer 40

The coast builds outwards ( and vice versa for negative)

Question 41

Define sediment cells.

Answer 41

Lengths of coastline that are self-contained for the movement of sediment.

Question 42

Why are sediment cells closed systems?

Answer 42

Because processes In one cell don’t affect movement of sediment in another cell