Component 2 - Coastal Change and Conflict Flashcards
What are the 3 types of mass movement?
1.Slides - material shifts in a straight line
2.Slumps - material shifts with rotation
3.Rockfalls - material breaks up and falls down the slope
What are examples of mechanical weathering?
1.hydraulic action
2.abrasion
3.attrition
What is chemical weathering?
The breakdown of rock by changing its chemical composition, eg carbonation weathering
What is hydraulic action?
waves crash against the rock and compress air in the crack, causing pressure to build, breaking a piece off/
What is abrasion?
eroded particles in the water scrape and rub against rock,
What is attrition?
eroded particles in the water smash into eachotehr becoming smaller. Their edges get rounded off too
What is a discordant coastline?
When the coastline is made up of alternating bands of hard and soft rock, at right angles to the coast
What is a concordant coastline?
the alternating bands of hard and soft rock are parallel to the coast
What landforms are made at discordant coastlines and why?
1.bays and headlands are formed
2.because the bands of rock are being eroded at different rates.
How does the UK’s climate impact its coastlines?
1.Strong winds cause destructive waves which increase erosion of cliffs
2.Intense rainfall makes cliffs more saturated so mass movement occurs more.
3.The prevailing winds from the south west bring storms in, which batter the coast and erode it
What are the properties of destructive waves?
1.large, steep and have a high frequency (10-14 a min)
2.Their backwash is more powerfu than their swash, so they remove material from the coast.
How do waves erode cliffs?
1.The wave forms a wave cut notch by erosion
2.The rock above becomes unstable and collapses
3.This material is washed away and the cycle continues
4.This causes cliffs to reteat.
5.It also leaves a wave cut platform
How are headlands eroded?
CCASS
1.Waves crash into the headland and enlarge cracks by hydraulic action and abrasion
2.this continues until a cave forms
3.This continues until it breaks through the headlands and forms an arch
4.Erosion weathers away the rock supporting the arch, causing it to collapse
5.This forms a stack, which is then further eroded into a stump, causing the headland to retreat
What is LSD?
Long shore drift - 1.Waves follow the prevailing wind
2.This means they usually hit the coast at an oblique angle
3.The swash carries material up the beach, with the waves
4.The backwash then carries it at right angles back out.
5.This repeats and carries material down a coastline
What is deposition?
When material being carries by water is dropped on a coast.
What are the properties of constructive waves?
1.They deposit more than they erode
2.They are low, long and have a low freq.(6-8waves)
How are spits formed?
1.LSD transports material down a coast, until it arrives at a sharp bend
2.The waves lose their energy and deposit material here
3.This continues until a spit forms.
4.Strong winds and waves can form a recurved end at the end of a spit.
What happens to the land behind a split?
it becomes sheltered, so lots of material accumulates and plants begin to grow. This then becomes a salt marsh.
How are bars formed?
1.When a spit joint 2 headlands togther
2.It cuts off the bay from the sea, forming a lagoon
BIG WARNING - CHECK OS MAP LABELS BEFOREHAND PLS
yoko geri - side thrust kick
How does agriculture affect the coast?
1.Agricultural land is of low value, so is left unprotected meaning that it is left to be eroded by the sea
2.Clearing vegetation for crops exposes the soil, making it vulnerable to weathering
3.marshland is often drained for use, this removes a natural flood barrier
How does development affect the coast?
1.Coasts with lots of settlement have more coastal defences so they erode slower there
2.This means that tranportation and deposition of material along the coast is change, so places along the coast may get more or less deposition
How does industry affect the coast?
- Coastal quarries expose lots of rock, making it exposed to erosion and weathering
- Gravel is taken from beaches to use in construction. This means there is less to protect the coast.
How does climate change and rising sea levels increase the risk of coastal flooding and erosion?
1.It will cuase higher tides, sos coastal areas flood more often
2.Higher tides remove larger amounts of material from beaches, leading to more erosion
How does climate change and storm frequency increase the risk of coastal flooding and erosion?
1.Storms give the sea more power, so the coast will become more vulnerable to all types of erosion
2.The sea will be able to transport more material, so many areas would be starved of material
3.Storm surges will flood areas further in land too
How does climate change threaten people on the coast?
- Low lying coastal areas might become permanently flooded.
- Coastal industries may be shut down due to damage to equipment from storms and sea levels
- There’s a risk of damage to coastal infrastructure
- The tourist industry will be hurt
How does climate change threaten the environment on the coast
- Ecosystems will be affected as seawater is harmful to creatures and lower soil fertility
- The force of floods can uproot trees and plants
- Lagoons can be destroyed as the bar is overwhelmed
What is hard engineering?
Man made structures built to control the flow of the sea and reduce flooding and erosion.
What is soft engineering?
Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion
What hard engineering defence methods are there?
- sea walls
- groynes
What soft engineering methods are there?
1.beach replenishment
2.slope stabilisation
3.strategic realignment
What are groynes and sea walls?
- Wooden or stone fneces built at right angles to the coast. These trap material being transported by LSD
- A wall made out of hard material that reflects waves back out to sea
What are the pros and cons of sea walls?
pros:
- Prevents erosion of the coast
- Acts as a barrier to prevent flooding
cons:
- creates stronger backwash, which erodes under the wall
- very expensive to maintain and build
What are the pros and cons of groynes?
Pros:
- they create wider beaches which slow the waves, providing greater protection from flooding and erosion
- they are fairly cheap
cons:
- They starve beaches further down the coast of sand
- This makes beaches narrower, and increases erosion and flooding down the coast
What is beach nourishment, slope stabilisation and strategic realignment?
1.Sand from elswhere or from lower down the beach is added to upper parts of beaches
2.Slopes are reinforced by covering it with metal netting
3.Removing an existing defence and allowing the land behind it to flood
What are the pros and cons of beach nourishment?
Pros:
- It creates wider beaches, which slow the waves and provide protection
cons:
- Taking material from the seabed can kill organisms like sponges and corals
- It’s very expensive and must be constantly replenished
What are the pros and cons of slope stabilisation?
Pros:
- It prevents mass movement by increasing the strength of the slope
Cons:
- Very expenisve and difficult to install
What are the pros and cons of strategic realignment?
Pros:
- Over time the land will become marshland, creating new habitats and resuding erosion behind the marsh
cons:
- people may disagree over what land should flood
What is a sustainable way to manage the coast?
Through the Integrated Coastal Zone Management (ICZM), who protect the coast whilst taking on everyone’s interests.
