Comp 2 Topic 4 - Coastal Change And Conflict

Question 1

What is mechanical weathering?

Answer 1

It is the breakdown of rock without changing its chemical composition. Theres one main type that affects coasts- salt weathering

1) the saltwater gets into the cracks in the rock
2) when the water evaporates salt crystals form. As the salt crystals form they expand which puts pressure on the rock.
3) repeated evaporation and the forming of salt crystals widens the cracks and causes the rock to break up.

Question 2

What is chemical weathering?

Answer 2

Chemical weathering is the breakdown of rock by changing its chemical composition. Carbonation weathering is a type of weathering that happens in warm and wet conditions.

1) seawater and rainwater have carbon dioxide dissolved within them which makes them weak carbonic acids
2) the sea water reacts with rocks that contain calcium carbonate, so rocks like limestone are dissolved by seawater and rainwater

Question 3

What is biological weathering?

Answer 3

It is the breakdown of rocks by living things. E.g. plant roots break down rocks by growing into crack on their surface and pushing them apart

Question 4

What is mass movement?

Answer 4

Mass movement is the shifting of rocks and loose material down a slope
It causes coasts to retreat rapidly
When the material is full of water it acts as a lubricant and makes the material heavier
There are three types of mass movement
Slides- material shifts in a straight line
Slumps- material shifts with a rotation
Rockfalls- material breaks up and falls down a slop

Question 5

What is hydraulic power?

Answer 5

Waves crash against the cliffs and compress the air in the cracks. It puts pressure on the rock. Repetition of this makes rock break off.

Question 6

What is abrasion?

Answer 6

Eroded particles in the water scrape and scratch on the rock , removing small pieces

Question 7

What is attrition?

Answer 7

Eroded particles of rock in the water smash against each other and break into smaller fragments. Their edges get rounded off as they rub

Question 8

What is a concordant coastline?

Answer 8

It is a coastline that has alternating bands of hard and soft rock parallel to the sea
It means it erodes at an even rate along the coastline and that there are fewer erosional landforms
Example is the white cliffs of dover
Coves and cliffs are common

Question 9

What is a discordant coastline?

Answer 9

Perpendicular to the sea
The rock erodes at different rates
Holderness
Headlands and bays formed

Question 10

How has climate affected costal erosion and retreat?

Answer 10

Mild temperatures increases rates of salt weathering
Storms create high power destructive waves
Heavy rainfall can increase mass movement
The UKs south coast is exposed to storms because the prevailing wind comes from that direction

Question 11

How do destructive waves wear away the coast?

Answer 11

The waves that cause erosion are called destructive waves.
They are high and steep and have a high frequency
Their backwash is more powerful than their swash so more material is removed than deposited
Storms increase the strength of the swash so more material is removed

Question 12

How are wave-cut platforms formed?

Answer 12

1) waves cause erosion mostly at the foot of the cliff (where the cliff meets the sea)
2) This forms a wave cut notch which enlarges as erosion continues
3) The rock above the rock then collapses
4) The collapsed material is washed away and a new wave cut notch is formed
5) repeated collapsing results in cliffs retreating
6) a wave cut platform is what is left as the cliff retreats

Question 13

How are headlands and bays formed along discordant coastline?

Answer 13

1) Headlands and bays are formed by alternating bands of resistant and less resistant rock along the coast
2) The less resistant rock erodes quickly and forms a bay- they have gentle slopes
3) The resistant rock is eroded more slowly and is left jutting out- they have steep sides

Question 14

How are headlands eroded into caves, arches and stacks?

Answer 14

1) headlands are usually made of resistant rock with weaknesses like cracks.
2) The cracks get bigger via hydraulic action and abrasion
3) The repeated erosion causes a cave to form
4) continued erosion causes the cake to break through to the other side
Forming an arch ( durdle door in Dorset)
5)Erosion continues eroding the rock supporting the arch and the arch collapses
6) this forms a stack which is later eroded into a stump (old harry in Dorset)

Question 15

What is transportation?

Answer 15

1) waves follow the direction of the prevailing
2) they usually hit the coast at a oblique angle (any angle that isn’t a right angle)
3) the swash carries material up the beach
4) the backwash carries material down the beach towards the sea
5) over time material zigzags along the coast

Question 16

What is a constructive wave?

Answer 16

Waves that deposit more material than they take are called constructive waves
They are low long and have a long frequency
The swash is powerful and carries material up the beach
The backwash is weaker and cannot erode very much
They deposit materials such as sand and shingle

Question 17

What is a spit?

Answer 17

1) they form at sharp bends in the coastline. E.g. at a river mouth
2) longshore drift deposits material past the bend in the sea
3) wind and waves can curve the end of the spit and give it a recurved end
4) a sheltered area is formed behind the spit, lots of material accumulates here and plants grow
5) over time this area can become a salt marsh or mud flat

Question 18

What is a bar?

Answer 18

A bar is formed when a spit joins two headlands together
The bar cuts off the bay between the headlands from the sea
It forms a lagoon

Question 19

To identify depositional landforms on a map?

Answer 19

Check page 53 CGP

Question 20

How has agriculture affected the coast?

Answer 20

-Agricultural land has a low economic value which means its often left unprotected. This means erosion can erode the cliffs.
-Vegetation helps bind the soil together and strengthen clifftops, clearing this vegetation for crops can expose the soil and underlying rock, making it susceptible to weathering from wind and rain
-marshland is sometimes reclaimed and drained for agricultural use, It reduces the natural flood barrier that marshlands provide
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Question 21

How has development affected the coast?

Answer 21

• Coasts are popular places to live and work so they have lots of development. Houses and infrastructure
• Coasts with lots of settlements on them are protected against erosion through sea defences. This has a positive direct effect on the coastline because the land is better protected.
• An indirect effect that arises from building coastal defences that trap sediment is that there is much less sediment moving down the beach through longshore drift so the areas down the beach are much less protected and vulnerable

Question 22

How has Industry affected the coast?

Answer 22

• Coastal quarries expose large areas of rock making them vulnerable to all types of erosion
• Gravel has been taken from beaches to make concrete, this decreases the barrier between the land and the sea.
• Ports are being built on salt marshes which are natural flood barriers so building on them makes the area more vulnerable

Question 23

How has Coastal management affected the coast?

Answer 23

• Coastal Management is about protecting the coast from erosion
• Methods that trap sediment increase erosion down the beach
• Coastal defences reduce erosion and therefore stop the land from retreating or changing

Question 24

Describe the Holderness coastline

Answer 24

• It stretches from a headland to a spit
• It has a high rate of erosion 1.8m every year is lost
• cliffs made of weak boulder clay, slumps easily
• Narrow beaches provide no protection from waves
• It faces the prevailing wind. Hit by high power waves from Norway
• eroded material is moved along the coast exposing more cliff to erosion

Question 25

How is the Holderness coastline being protected?

Answer 25

- Over 11km is protected by hard engineering strategies due to: Towns and villages with populations exceeding 6000 (hornsea, withernsea,mappelton) There is the B1242 road which connects many towns There is a gas terminal on the cliff which provides 25% of UK fuel -coastal defences such as groynes have been built at mappleton There are groynes and sea walls at hornsea and withernsea

Question 26

How have Holderness defences affected areas down the coast?

Answer 26

- Groynes have helped local areas however it has meant that beaches down the coast are thin. Caravan parks and farms are at risk of falling into the sea. - material from erosion in holderness in transported to the estuary if less eroded material is being produced the estuary is at risk - The lincolnshire coasts and spurn head has had increased erosion becase there is less material to add to them - maintaining the area is becoming more expensive because the protected areas are becoming headlands which are eroded more heavily

Question 27

How is rising rising sea level having an affect on coastal flooding?

Answer 27

- Higher sea levels pose a threat to low lying areas - Higher sea levels would cause higher tides that would flood coastal areas more frequently - higher tides could also remove larger amounts of material from beaches - Beaches would become narrow as the sea could could come further inland.

Question 28

How is storm frequency having an affect on coastal flooding?

Answer 28

- Climate change is causing storm frequency to become more frequent - storms give the sea more erosional power, areas of hard rock are more vulnerable, areas of soft rock erode more quickly - The sea has more energy to transport material leaving some areas starved of material - Storm surges could become more frequent, sea levels could cause surges to reach further inland

Question 29

How is climate change having an affect on people living in coastal communities?

Answer 29

- Low lying areas could become permanently flooded - Coastal industries may be shut down because of flood damages - Risk of damage to infrastructure like roads and railways. Railways in Devon run parallel to the sea and were damaged in 2014 - Tourists are less likely to go and spend money, businesses that rely on tourism are badly affected, loss of livelihoods

Question 30

How is climate change having an affect on the environment in coastal communities?

Answer 30

Ecosystems will be affected because of the high salt water. The levels of salt can kill organisms and affect land fertility - The force of floodwater can uproot trees and plants. Standing floodwater drowns trees and plants - conservation lagoons could be destroyed if the saltwater breaks through the bar into the lagoon.

Question 31

What is hard engineering?

Answer 31

Man made structures built to control the flow of the sea and reduce flooding and erosion

Question 32

What is soft engineering?

Answer 32

Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion

Question 33

What is a sea wall, what are the benefits and costs?

Answer 33

A wall made out of a hard material that reflects waves back out to sea It prevents erosion of the coast, it acts as a barrier to prevent flooding Sea walls are very expensive to build and maintain due ti the backwash that erodes underneath them

Question 34

What are groynes, what are the benefits and costs?

Answer 34

Wooden or stone fences that are built at right angles to the coast, they trap material transported by longshore drift They create wider beaches which slow the waves They starve beaches further down the coast making them narrower

Question 35

What is replenishment, what are the benefits and costs?

Answer 35

- sand and shingle from elsewhere or lower down the beach is added to the upper part of the beach - It creates wider beaches which slow waves, greater protection form flooding and erosion - It can kill organisms such as coral and sponges, it is very expensive and has to be repeated

Question 36

What is slope stabilisation, what are the benefits and costs?

Answer 36

Slopes are reinforced by inverting concrete nails into the ground and covering the slope with metal netting - it prevents mass movement by increasing strength of the slope - it is very expensive and difficult to install

Question 37

What is strategic realiginment, what are the benefits and costs?

Answer 37

- Removing an existing defence and allowing the land behind it to flood - over time the land will become marshland creating new habitats. Flooding and erosion are reduced behind the marshland - people may disagree over what land can be flooded, for example flooding of farmland may affect farmers livelihoods

Question 38

What is happening to make management strategies sustainable?

Answer 38

People need to make sure that erosion and flooding are controlled without causing more problems elsewhere or affecting people in the area. ICZM aims to take everyone interests into account, it makes it easier to find solutions