Coasts Flashcards
How is Bridlington being protected in the Holderness coast?
There is a 4.7 km sea wall as well as groynes that stop material being moved.
What is the rate of erosion in the holderness coast?
1-2 meters every year.
100 s of rocks are eroded every tide.
Mappulton was 4km away from the sea 200 years ago.
6 houses have gone in the last 15 years.
How is Hornsea being protected in the Holderness coast?
There is a sea wall, wooden groynes and rock armour. This is because it is a popular tourist resort so money would be lost if it wasn’t protected.
How is Mapperlton being protected in the Holderness coast?
In 1991 half the towns budget was spent on two million pound rock groyne. This collects material which stops erosion. Only 100 people live there and the houses aren’t worth saving but the B1242 road goes through it. It would cost millions to re-route it so it is being protected.
What are the consequences of the rock groyne at Mappulton?
It means no material can get further down the coast to replenish the eroded material. The farm land there is being eroded and people have to be moved. The land isn’t worth much so it is left.
At Great Cowden that rate of erosion is 10m per year.
How is Withernsea being protected in the Holderness coast?
Groynes have been put in place to create a wider beach. There is also a sea wall and rock armour in front of it.
How is Easington being protected in the Holderness coast?
A sea wall was put up. This is because there is a gas refinery which produces 20% of the UK’s gas there.
How is Spurn Head being protected in the Holderness coast?
The eastern side has groynes and rock armour. This is because groynes put up along the coast prevent LSD from moving material to the spit.
Why is there such a large rate of erosion in Holderness?
The cliffs are made of boulder clay which is likely to slump when wet, causing cliff collapse.
The beaches are narrow meaning they can’t absorb the power of the waves.
Holderness faces the prevailing wind. Waves from the north west( all the way from the arctic ocean) there is a long fetch meaning the waves are very powerful.
Groynes are capturing material meaning it can’t be replenished when eroded.
What is the effect of such high erosion at the Holderness coast?
80,000 square meters of farm land is lost each year meaning farmers lose money.
Businesses are at risk. The seaside Caravan Park loses 10 pitches a year.
Property prices have fallen and it is hard to insure them.
Some SSSIs are threatened. Lagoons near Easington are being protected by a bar. If this is eroded the lagoons will be destroyed.
What and where are the Maldives?
There are a collection of 1190 islands south of India in the Indian Ocean. 300,000 people live there.
80% of the islands are less than 1m below sea level. Sea levels go up by 9mm a year and experts say they will be gone between 50-100 years.
What are the economic effects of coast flooding in the Maldives?
Tourism is the largest industry in the area. If the airport can’t function because of flooding international tourists won’t be able to come which will massively reduce the income.
Fish is the islands largest export. Coastal flooding may damage fish processing plants, reducing the fish exports and the country’s income.
What are the social effects of coast flooding in the Maldives?
Houses are damaged or destroyed. A flood could make entire communities homeless. People would have to be re housed and public buildings rebuilt.
Less fresh water available. Supplies are already low and a flood would contaminate water. Some islands would depend on rain water or have to buy expensive desalination plants.
What are the environmental effects of coast flooding in the Maldives?
Coastal flooding means beaches are worn away and habitats are destroyed or left exposed if it’s the land behind beaches.
The soil layer is about 20cm. A flood could wash the soil away meaning nothing will grow.
What are the political effects of coast flooding in the Maldives?
The Maldivian Government asked the Japanese Government for $60 million to build a 3m high sea wall around the capital of Malé.
The Maldives has pledged to become carbon neutral so stop the effects of global warming. It want’s other nations to do the same.
The government is thinking about buying land in India and Australia and moving people there before the islands become uninhabitable.
What is mechanical weathering?
The breakdown of rock without changing its chemical composition.
Explain freeze thaw weathering.
It occurs when the temperature alternates above and below 0 degrees.
Water gets into cracks in a rock.
When it freezes it expands putting pressure on the rock.
When it thaws it contracts, the pressure is released.
Repeating the process means the rock breaks up.
What is chemical weathering and give an example.
The breakdown of rock by changing its chemical composition. Carbonation weathering happens in warm and wet climates.
Rainwater with co2 in it becomes a weak carbonic acid. This reacts with calcium carbonate so the rocks are destroyed.
What is mass movement?
This shifting or rocks and loose material down a slope. It happens when the force of gravity is greater than that of the force supporting it.
It causes coastlines to retreat rapidly.
Is is more likely to happen when the land is full of water as it weighs the cliff down and acts asa lubricant.
What is slide?
Mass movement when material shifts in a straight line.
What is a slump?
Mass movement when material shifts with a rotation.
What are the four types of erosion?
Hydraulic, abrasion, attrition,solution.
Explain hydraulic power.
Waves crash against rock and compress air in the cracks creating pressure. Repeated pressure widens the cracks causing erosion.
Explain abrasion.
When the sea hurls stones at a cliff face, causing bits to break off.
Explain attrition.
Eroded particles in the water smash together and break into smaller fragments.
Explain solution.
Weak carbonic acid in seawater dissolves chalk and limestone.
Explain destructive waves.
They carry out the erosion all processes.
High have a high frequency. (10-14 waves a minute)
High and steep.
The backwash is more powerful than the swash meaning they move material down the beach.
More common in winter.
How are wave cut platforms formed?
Waves eroded the foot of a cliff the most.
This form wave cut notches which is enlarged as wearing and erosion continues.
The rock above the notch will become unstable and collapse.
This collapsed material is washed away and a new wave cut platform will start to form.
Repeated collapsing results in the cliff retreating.
A wave cut platform is what’s left when the cliff has retreated.
How do headlands and bays form?
Along a coast there will be alternating bands of hard and soft rock. Some will be resistant to erosion, some won’t.
The soft rock is eroded quickly and this forms a bay which will have a gently slope.
The hard rock is eroded more slowly and is left jutting out forming a headland with steep sides.
How do caves, arches and stacks form in headlands?
Headlands are made of strong rock but it still has weaknesses in the form of cracks.
Waves crash into headland and enlarge the cracks, mainly be hydraulic power and abrasion.
When this is repeated the cracks will get bigger and form a cave.
Repeated erosion will deepen the cave until it breaks through the headland forming an arch.
Erosion continues to wear away the rock that’s supports the arch until it collapses.
This forms a stack which is an isolated rock that is separate from the headland.
What is Long shore drift?
It transports material along the coast.
Waves will follow the direction of the prevailing wind.
This means they usually hit the coast at an angle.
The swash will carry material in the same direction as the waves.
The backwash will then carry the material back down again at right angles back towards the sea.
Overtime material will be zigzagged along the coast.
When drawing a diagram of LSD what must you remember to have?
Arrow for direction of prevailing wind.
Arrow for direction of material movement.
Arrow for swash and backwash.
Key for the arrows.
What is deposition and when does it happen?
It is when material being transported by the sea is dropped along the coast.
Coasts ate built up when the rate of deposition is greater than the rate of erosion.
The amount of deposition is increased when
There’s lots of erosion elsewhere along the coast giving material
There’s lots of transportation of material into the area.
Low energy waves cause the most deposition as they aren’t strong enough to take material away.
