4A - Coastal Change and Conflict Flashcards
What are the 2 types of waves?
- Destructive
- Constructive
State the definition of the backwash.
- Water that runs back down the beach under gravity.
Define swash.
- Water that surges up the beach until it runs out of energy.
Describe the characteristics of a destructive wave.
- Strong winds blown over long fetches
- Tall and steep
- Stronger backwash than swash
- Frequently break
State the characteristics of a constructive wave.
- Light winds and short fetches.
- Less energy, encourages deposition.
- Low in height and breaking gently.
- Stronger swash than backwash.
What is a fetch?
- Distance over which the wind is blowing.
ESQ - Explain the difference between a discordant and a concordant coast. [4]
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].
ESQ - Explain how an arch and a stack are formed from a combination of different processes. [4]
- 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]
How is a wave cut platform formed?
- 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.
Give the 3 types of weathering.
Mechanical Weathering.
Biological Weathering.
Chemical Weathering.
Explain the process of chemical weathering using rain as an example.
Rain falling on rocks makes a small chemical reaction occur, eventually weakening and breaking down the rock.
Give an example of the climate of an area impacting the type of weathering in operation.
Heavy rainfall in sloped areas adds volume and weight to the soil, inducing mechanical and chemical weathering.
Define longshore drift.
The movement of sand and pebbles along the coast via waves.
How are beaches formed?
Eroded material is transported by longshore drift and deposited by constructive waves along the coastline.
Define a spit.
A long and narrow ridge of sand and shingle.
Give the definition of a bar.
A ridge of sand or shingle across the entrance to a bay.
How is a bar formed along an entrance to a bay?
- 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.
Explain 2 examples of when human causes can impact coastal erosion.
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.
Define a storm surge.
A large-scale increase in sea level due to a storm.
How does global warming cause rising sea levels?
This causes seawater expansion and melting of ice sheets and glaciers, which causes sea levels to rise.
Describe the advantages and disadvantages of protecting a coastline using sea walls.
Advantages:
- Protects cliff base.
- Resistant concrete.
- Reflects energy when recurved.
Disadvantages:
- Expensive
- Limited beach access.
- Eyesore.
Describe the advantages and disadvantages of using beach replenishment.
Advantages:
- Looks natural.
- Attracts tourists.
- Cheap
Disadvantages:
- Material easily transported away.
- Needs regular replacement.
Give an advantage and disadvantage of the use of groynes.
Advantage - Attracts tourists
Disadvantage - Needs high maintenance.
