Coastal Environments

Question 1

What are the Inputs, Processes and Outputs of a coast?

Answer 1

Inputs - River sediment, cliff sediment and sediment from waves.

Processes - Wave action, Tidal action, erosion, weathering, transportation, deposition.

Outputs - Sediment washed out to sea or deposited further along the coast.

Question 2

What are coastal sediment cells?

Answer 2

A stretch of coastline that is completely self contained. Its processes do not affect another cell along the coast.

Question 3

Describe what happens to the flow “shape” of a wave as it comes inshore?

Answer 3

When the wave is out at sea, the water moves round in a circular orbit. However, as the wave comes inland it becomes flatter as the depth decreases, the orbit of the water becomes an oval shape and a wave crest begins to form. The orbit of the water becomes more and more ovular until the wave collapses and breaks.

Question 4

Define swash?

Answer 4

When water moves up the beach, depositing sediment.

Question 5

Define backwash?

Answer 5

When water moves down the beach, taking sediment.

Question 6

Define fetch?

Answer 6

The maximum distance of sea that the wind has blown over to create the waves.

Question 7

what do you need to create high waves?

Answer 7

A high wind speed and long fetch.

Question 8

What feature of a wave defines what effect it will have on the shore?

Answer 8

The height of the wave.

Question 9

Describe a constructive wave?

Answer 9

They have a low frequency. They are low and long which makes them look elliptical. They have a powerful swash that deposits a lot of sediment on the beach.

Question 10

Describe a destructive wave?

Answer 10

High frequency. They look more circular than constructive waves. A strong backwash takes sediment from the beach.

Question 11

What creates tides?

Answer 11

The gravitational pull from the moon and the sun.

Question 12

Give two examples of sub-aerial weathering?

Answer 12

Freeze-thaw weathering and Salt weathering.

Question 13

What is the effect of weathering on coasts?

Answer 13

Weathering weakens cliffs and makes them more vulnerable to erosion.

Question 14

What is throughflow?

Answer 14

Water running over the cliffs. This can make them less stable and lead to mass movement.

Question 15

What is mass movement? Give 2 examples?

Answer 15

The movement of material downhill due to gravity.

Landslides, slumping, rockfalls

Question 16

Waves erode the coastline in 5 ways. Name and explain 3?

Answer 16

Abrasion - bits of rock and sediment in the waves smash against the cliffs, breaking bits off and smoothing the surface.

Hydraulic action - Air which is trapped in cracks in the cliff is compressed when the waves come in, causing them to break bits of rock off.

Quarrying - The energy of a wave is enough to break bits of the cliff off.

Corrosion - Soluble rocks are gradually dissolved by the seawater.

Attrition - When rocks in the water collide and break into smaller bits.

Question 17

Which factors effect the rate at which a coastline erodes? Name and explain 3?

Answer 17

The width of the beach - Beaches slow down the waves, reducing their power.

The breaking point of the waves - If a wave breaks directly onto a cliff then it will erode it with full force.

The aspect - When a coastline is facing the dominant wind direction, it will erode faster.

The fetch of the waves - Waves with a larger fetch are more powerful and cause more erosion.

Rock type - Some rocks erode more easily than others.

Question 18

What is longshore drift?

Answer 18

When a current moves material along the coast.

Question 19

Which coastal landforms are caused by erosion? name 3?

Answer 19

Cliffs, Headlands, Bays, Caves, Arches, Stacks.

Question 20

Which coastal landforms are caused by deposition? name 3?

Answer 20

Beaches, Spits, Bars, Sand dunes, Salt marshes.

Question 21

Waves erode the coastline in 5 ways. Name and explain 3?

Answer 21

Abrasion - bits of rock and sediment in the waves smash against the cliffs, breaking bits off and smoothing the surface.

Hydraulic action - Air which is trapped in cracks in the cliff is compressed when the waves come in, causing them to break bits of rock off.

Quarrying - The energy of a wave is enough to break bits of the cliff off.

Corrosion - Soluble rocks are gradually dissolved by the seawater.

Attrition - When rocks in the water collide and break into smaller bits.

Question 22

Which factors effect the rate at which a coastline erodes? Name and explain 3?

Answer 22

The width of the beach - Beaches slow down the waves, reducing their power.

The breaking point of the waves - If a wave breaks directly onto a cliff then it will erode it with full force.

The aspect - When a coastline is facing the dominant wind direction, it will erode faster.

The fetch of the waves - Waves with a larger fetch are more powerful and cause more erosion.

Rock type - Some rocks erode more easily than others.

Question 23

What is longshore drift?

Answer 23

When a current moves material along the coast.

Question 24

Which coastal landforms are caused by erosion? name 3?

Answer 24

Cliffs, Headlands, Bays, Caves, Arches, Stacks.

Question 25

Which coastal landforms are caused by deposition? name 3?

Answer 25

Beaches, Spits, Bars, Sand dunes, Salt marshes.

Question 26

Why is coastal flooding now more likely?

Answer 26

Due the rising sea levels.

Question 27

What are the causes of Eustatic sea level changes? Who does it effect?

Answer 27

Eustatic sea level changes are caused by the change in the volume of water in the sea, or a change in the shape of the ocean.

The effects are global. Everyone is effected.

Tectonic plate movements - sea floor spreading increases the basin’s volume and this reduces sea level.

Changes in climate -

1. An increase in temperature causes ice sheets to melt, making the sea level rise.
2. A decrease in temperature causes more snow precipitation which increases the size of glaciers, decreasing sea level.

Question 28

What are the causes of Isostatic sea level changes?

Answer 28

Changes in height of the land. Downward movement of the land causes the local sea level to rise. Upward movement of the land causes the local sea level to fall.

The effects are always local.

Question 29

Sea level rise has three main impacts. Name 2?

Answer 29

More frequent and severe flooding.

The submergence of low-lying islands.

Changes in the coastline.