Geography Coastal Zone (Physical)

What causes waves?
When wind blows across the sea, friction between the wind and water surface causes waves
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What does the size of the wave depend on?
The strength of the wind, How long the wind blows for, the length of water the wind blows over (FETCH)
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Which type of wave erodes the most?
The destructive waves
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Compare the different types of waves?
Destructive waves are high in proportion to their length, the backwash is much stronger than the swash, they are frequent waves and they're most comoon in winter. Constructive wave build beaches as the waves are low and they're most common in summer.
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What are the 3 types of weathering?
Mechanical (physical - freeze-thaw weathering) Chemical (solution)
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What is mass movement?
The downhill movement of material under the influence of gravity
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What are the 4 processes of Coastal erosion?
Hydraulic Action (sheer force of the waves) Abrasion (loose sediment) Attrition (Particles/smaller sediment) Solution
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What are the 4 main types of sediment transport?
Traction (rolled) Saltation (bounce) Suspension (carried) Solution
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Define Long shore drift
The movement of sediment in the direction of the prevailing wind (a zig zag pattern) through swash and backwash
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What is a headland?
A point of high land that juts out into the sea
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What is a Bay?
Is a broad coastal inlet that often has a beach
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What is a wave cut notch?
It's a 'bite' out of the cliff base and creates an overhang above it
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What is a wave cut platform?
It's formed through the gradual retreat of the cliff (wave cut platform sequence) A genlty sloping rocky platform will be left behind.
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Describe how a cave is formed?
A cave is formed when weak areas of rock are attacked by the waves through hydraulic action.
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How is an arch formed?
An arch is formed when the cave is eroded further and breaks through to the other side
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What happens after an arch in a headland?
A stack is when the roof collapses in an arch due to weathering and gravity and leaves an isolated piece of rock. A stump is when the stack is undercut and there is just a small piece of rock left behind.
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What is a beach?
Is a mixture of sand and pebbles which have been depositied by the water because it has lost energy as it has entered the bay
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What is a spit?
Is a narrow finger of sand and shingle jutting out into the sea and they're most likely to be formed where the coastline changes direction or where a river mouth enters the sea
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When is a bar formed?
It's formed when spits grow and meet in the middle, cutting of the bay as the 2 headlands
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Why has the sea level risen?
Global warming and thermal expansion
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What are the consequences of sea levels rising?
Erosion rates are likely to increase and salt marshes could be lost
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What are spring tides?
Exceptionally high tides which occur when the sun and moon are in alignment
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What parts of the UK are at risk if sea levels rise?
East and South Coasts
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What is the barrier of protecting London
The Thames Flood Barrier
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What coast in Yorkshire has a very high erosion rate?
Holderness coast
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Why do cliff collapse?
Cliff foot erosion, weathering, cliff face erosion, water flows through the permeable rock, adding to the weight of the cliff.
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Impact of Holbeck Hall Cliff Collapse (Scarborough South Cliff)
Lose homes to the sea, House values will fall and insurance may be difficult to get, dangerous, roads damaged, unnatractive
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Methods that can be used to stop cliff collapse
Land Flatter, Plant salt resistant vegetation, insert drainage pipes, rock armour, pack clay
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What 4 ways the councils can choose between when they make decisions about how best to manage the coast
Hold the line, Advance the line, Strategic retreat, Do nothing
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Hard Engineering - Sea wall evaluation
A concrete or rock barrier to the sea (3-5m high) Cost up to £6 million per Km, Adv - Effective at stopping the sea Dis- Prevent easy access to the beach
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Hard Engineering - Groynes evalutation
Trap sand by stopping longshore drift, Cost £10,000 each Adv- Larger beach dissipates wave energy, reducing erosion Dis- Interupt longshore drift
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Hard Engineering - Rock armour evaluation
Piles of large boulders placed at the foot of the cliff Cost £1000-4000 per metreAdv- Easy to build Dis- Expensive to transport
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Soft Engineering - Beach Nourishment evaluation
Addition of sand or shingle Cost - £3000 pe metre Adv- Blends in with existing beach Dis- Needs constant maintenance
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Soft Engineering - Dune Regeneration evaluation
Sand dunes are effective buffers to the sea yet they are easily damaged (marram grass) Cost- £2000 per 100m Adv- Relatively cheap Dis- Time consuming
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Soft Engineering - Marsh Creation evaluation
The cost depends on the value of the land (£5000-10,000 per hectare) Adv- Creates a much needed habitat Dis- Land will be lost as it's flooded.
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What is management retreat?
Is allowing controlled flooding of low-lying coastal area or cliff collapse in areas where the value of land is low.
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What does Holistic Management involve?
Needs of different people, Economic costs and benefits of different strategies today and the future, Environment, both on land and in the sea
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The Case Study of Holderness Coast
Extends 61km. 29 villages lost to the sea in the past 1000 years - Rock Type = Boulder Clay - Rain = unstable - Long Fetch = increases wave energy for erosion - Destructive waves - Material is rapidly removed by the sea - Exposed coastline
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Mappleton's Coastal Defences
1991 - £2 million spent on a coastal protection scheme only due to the bus route which passed through
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What are the conditions needed for Sand dunes?
A large are exposed between high and low tides, Prevailing onshore winds, large supply of fine sand, arid environments, salt spray, alkaline conditions
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Sand dune sequence
Embryo Dunes, Fore dunes, Main ridge, grey dunes, matured dune
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Plant species with sand dune developments
Embryo Dunes = Lyme grass/sea couch grass, Fore Dune= marram grass, Grey Dune= heather and gorse, Mature dune= oak trees
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Case Study - Studland Heath
Up to 25,000 people visit on a summer day. Strategies involve: car parks (800 cars) - visitor centre - increased numbersof toilets - closed paths and fenced off parts - little bins - fire beaters and water hydraters
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Other cards in this set

Card 2


What does the size of the wave depend on?


The strength of the wind, How long the wind blows for, the length of water the wind blows over (FETCH)

Card 3


Which type of wave erodes the most?


Preview of the front of card 3

Card 4


Compare the different types of waves?


Preview of the front of card 4

Card 5


What are the 3 types of weathering?


Preview of the front of card 5
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