4A - Coastal Change and Conflict

Question 1

What are the 2 types of waves?

Answer 1

• Destructive
• Constructive

Question 2

State the definition of the backwash.

Answer 2

• Water that runs back down the beach under gravity.

Question 3

Define swash.

Answer 3

• Water that surges up the beach until it runs out of energy.

Question 4

Describe the characteristics of a destructive wave.

Answer 4

• Strong winds blown over long fetches
• Tall and steep
• Stronger backwash than swash
• Frequently break

Question 5

State the characteristics of a constructive wave.

Answer 5

• Light winds and short fetches.
• Less energy, encourages deposition.
• Low in height and breaking gently.
• Stronger swash than backwash.

Question 6

What is a fetch?

Answer 6

• Distance over which the wind is blowing.

Question 7

ESQ - Explain the difference between a discordant and a concordant coast. [4]

Answer 7

Extensions vary from starting point because of different attitude of rocks [1], causing difference in rates of erosion/retreat on discordant coasts [1], resulting in bays and headlands on discordant coasts [1]. Concordant coasts are more smooth/uniform [1].

Question 8

ESQ - Explain how an arch and a stack are formed from a combination of different processes. [4]

Answer 8

• Destructive waves break against the headland. Any line of weakness (faults/joints) are attacked. [1]
• Eroding the rock through hydraulic action and abrasion [1]
• Waves breaking traps air in the cave, increasing pressure, causing abrasion. It erodes to the other side, forming an arch [1]
• The arch collapses under pressure, forming a stack [1]

Question 9

How is a wave cut platform formed?

Answer 9

• Hydraulic action/abrasion forms a wave cut notch.
• Overhanging cliff becomes unsupported and collapses.
• Waves erode and undercut the new cliff face, over time causing the cliff face and coastline to retreat.
• A wave cut platform is formed.

Question 10

Give the 3 types of weathering.

Answer 10

Mechanical Weathering.
Biological Weathering.
Chemical Weathering.

Question 11

Explain the process of chemical weathering using rain as an example.

Answer 11

Rain falling on rocks makes a small chemical reaction occur, eventually weakening and breaking down the rock.

Question 12

Give an example of the climate of an area impacting the type of weathering in operation.

Answer 12

Heavy rainfall in sloped areas adds volume and weight to the soil, inducing mechanical and chemical weathering.

Question 13

Define longshore drift.

Answer 13

The movement of sand and pebbles along the coast via waves.

Question 14

How are beaches formed?

Answer 14

Eroded material is transported by longshore drift and deposited by constructive waves along the coastline.

Question 15

Define a spit.

Answer 15

A long and narrow ridge of sand and shingle.

Question 16

Give the definition of a bar.

Answer 16

A ridge of sand or shingle across the entrance to a bay.

Question 17

How is a bar formed along an entrance to a bay?

Answer 17

• Material transported via longshore drift.
• Deposited in a bend in the coastline.
• This continues in a line along the entrance.
• Sea water is trapped behind the bar to form a lagoon.

Question 18

Explain 2 examples of when human causes can impact coastal erosion.

Answer 18

Settlements - Villages built along the coastline can be lost due to coastal erosion.

Tourism - Structures such as groynes are built to trap sand. However, sediment removal from beaches result in increased erosion further down the coast.

Construction - Dredging removes sand from the beach. This can result in wave action eroding high beaches protecting villages, leaving the defenseless.

Question 19

Define a storm surge.

Answer 19

A large-scale increase in sea level due to a storm.

Question 20

How does global warming cause rising sea levels?

Answer 20

This causes seawater expansion and melting of ice sheets and glaciers, which causes sea levels to rise.

Question 21

Describe the advantages and disadvantages of protecting a coastline using sea walls.

Answer 21

Advantages:

• Protects cliff base.
• Resistant concrete.
• Reflects energy when recurved.

Disadvantages:

• Expensive
• Limited beach access.
• Eyesore.

Question 22

Describe the advantages and disadvantages of using beach replenishment.

Answer 22

Advantages:

• Looks natural.
• Attracts tourists.
• Cheap

Disadvantages:

• Material easily transported away.
• Needs regular replacement.

Question 23

Give an advantage and disadvantage of the use of groynes.

Answer 23

Advantage - Attracts tourists
Disadvantage - Needs high maintenance.