1. (The narrow contact zone between land and sea.)
Aiming for…
THE COASTAL ZONE
(The narrow contact zone between land and sea.)

2. There are 2 main types of Weathering
Freeze Thaw Weathering
Occurs when temp hovers around 0°C
Water seeps into rock cracks.
The water expands when it freezes – putting rock under pressure. Upon thawing the pressure is released.
Process repeats eventually causing rock to break.
Weathering 1.
Carbonation Weathering
Occurs in warm, wet conditions.
Water in the air mixes with CO2 to produce weak carbonic acid .
H2O CO H2CO3
Alkaline rocks such as chalk and limestone are dissolved by the acid.
There are 2 main types of Weathering 2.
Mechanical:
breakdown is physical break up of rock. At the coast this is by freeze-thaw 3.
Terminology
Weathering: the breakup or decay of rocks in their original place at, or close to, the earths surface
Chemical:
the chemistry of the rock is altered. At the coast this is mainly by carbonation, however salt spray can play a part.

3. Terminology Mass Movement Mass Movement a)Slides b) Slumps
Saturated material moves in a circular rotation as it is pulled down off the cliff. This is due to uneven distribution of mass or a folded curved slip plane.
Terminology
Mass Movement
The downhill movement of material under the influence of gravity
a)Slides
Drier material moves horizontally along bedding slip plane of rock.
Types of Mass Movement
Rockfall: fragments of rock break away from the cliff face, often due to freeze-thaw weathering
Landslide: blocks of rock slide downhill
Mudflow: saturated soil and weak rock flows down a slope
Rotational Slip: slump of saturated soil and weak rock along a curved surface

4. Wave Types
Constructive Waves: (Depositional)
Surge up the beach with a powerful swash
Carry large amounts of sediment and ‘construct’ beach
Formed by distant storms
Waves well spaced apart and powerful when they reach the coast
Destructive Waves: (Erosional)
Weak swash and powerful backwash
Scour the beach of material ‘destroying’ beach
Formed by local storms
Closely spaced and can interfere with one another, producing chaotic, swirling mass of water

5. Waves can erode the land by one of four processes
Hydraulic Action (Power)
Waves trap air in cracks in
the rock. The creates high pressure. Repeated compression widens cracks and breaks off rock
Abrasion (Corrasion)
Particles carried in the seawater scrape and rub against coastal rocks. This sandpaper effect removes small pieces from the coast.
Coastal Erosion
Waves can erode the land by one of four processes
Corrosion (Solution)
Seawater is a weak carbonic acid. If particles of alkaline rock e.g. chalk or limestone are carried in seawater they will eventually dissolve.
Attrition
Loose particles in the seawater collide with each other. This constant hitting against each other makes particles smaller and rounded because the edges are worn off.
Terminology
Erosion
the process by which rock or soil is gradually destroyed by wind, rain, or the sea

6. Coastal Transportation
Longshore Drift
Waves approach the beach at an oblique angle due to prevailing wind
The resulting swash pushes sediment up the beach
Sediment is carried back down the beach as the waves draw back
Traction: large pebbles are rolled along the seabed
Saltation: a ‘hopping’ or ‘bouncing’ motion of particles too heavy to be suspended
Suspension: particles are carried (suspended) within the water
Solution: dissolved chemicals often derived from limestone or chalk

7. Coastal Deposition
Coastal Deposition takes place in areas where the flow of water slows down.
Coasts are built up when the amount of deposition is greater than the amount of erosion
Energy of the water is lost due to friction against the sea bed, meaning the sediment can no longer be carried or rolled along and has to be deposited.
The amount of material deposited will increase when there is excessive erosion elsewhere on the coast, meaning that there is a lot of material to be deposited OR there is a lot of material transported into the area

8. Landforms Caused by Erosion
Headlands and Bays
Cliffs rarely erode at an even pace. Where coastlines are made up of different rocks, rock that is particularly resistant to erosion erode more slowly, forming headlands. Areas of weaker rock erode more quickly to form bays
Cliffs and Wave Cut Platforms
Waves cause most erosion at the foot of a cliff causing a wave-cut notch. This is enlarged as the erosion continues. This causes the rock above the notch to become unstable and eventually leads to cliff collapse. This process repeats over time, causing the cliff to retreat and leaves behind a wave cut platform

9. Landforms Caused by Erosion
Caves, Arches, Stacks and Stumps
Headlands are usually made of resistant rock that have weaknesses such as cracks.

10. Coastal Erosion at Holderness – Reasons for Erosion
Key Facts and Figures
Holderness is in East Yorkshire and has one of the fastest eroding coastlines in Europe
Flamborough Head (headland) is harder chalk
The majority of the coastline is made of soft blouderclay
Erosion rates (per year):
Flamborough = 0.1m
Average erosion = 1.8m
Clay cliffs = 10m
1. Easily eroded rock:
Boulder clay is likely to slump when wet, causing the cliffs to collapse
2. Narrow beaches
Beaches reduce energy of waves and therefore erosive power – narrow beaches give less protection
3. People
Coastal defences like groynes stop sediment moving down the coast, meaning beaches are even narrower
4. Powerful Waves
Holderness faces the prevailing wind. Waves gain power over the long distance and increase their erosive abilities.
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11. Coastal Erosion at Holderness – Impacts and Management
Social Impacts
Homes are at risk of collapsing into the sea in some areas such as Skipsea
Property prices have fallen significantly as a result
Roads at risk of collapsing has led to some areas are less accessible
Businesses, such as caravan parks, are at risk of collapse, so jobs will be lost and profits reduced
Easington Gas Terminal is at risk of collapse – it provides 25% of Britain’s gas supply
Environmental Impacts
SSSI’s (Sites of Special Scientific Interest) are threatened with destruction
For Example - The Lagoons at Easington are separated from the sea by a bar; if this is eroded and breached; this will connect the Lagoons to the sea; destroying them.

12. Landforms Caused by Deposition
1. Sand
Flat and Wide
Sand particles are small
Weak backwash able to move sand backwards to create a long, gentle slope
Beaches
Beaches are found between the high water mark (highest point on the land that the water will reach) and the low water mark. They are formed by constructive waves. There are 2 types of beach:
2. Shingle
Steep and narrow
Shingle particles are large
Weak backwash unable to move it back down beach
Particles build up to create a steep slope

13. Landforms Caused by Deposition
Spits and Bars
Spits are long, narrow finger shaped areas of sand or shingle that jut out into the sea. They are formed by longshore drift in areas where the coastline suddenly changes direction. They are attached to the coastline at one end. If it reaches out far enough to become attached to another piece of the mainland, it is called a bar.

14. Explain why cliffs collapse.

15. Cliffs collapse due to a number of reasons…
These often occur in combination with one another.
The power of the waves pounding against the base of the cliff between the HWM and LWM undercuts the cliffs and makes it unstable.
The overhanging parts will eventually collapse.
Heavy rainfall can add weight to the land and make it unstable, causing landslides or slumps to occur. This is especially likely if soft rock is present.
Adding buildings to the cliff tops can have similar effects – or even a lot of people walking on the cliff tops can have similar effects.
People protecting the coast and interfering with longshore drift can prevent the movement of the sand to replenish beaches and expose the base of the cliffs to erosion.

16. Discuss the costs and benefits of using hard engineering to reduce the risk of cliff collapse.

17. How Can Coastlines be Managed? – Hard Engineering
Hard Engineering Approaches
Hard Engineering involves using artificial structures to control the flow of the sea; reducing erosion and flooding. They are expensive and involve high maintenance costs
 Strategy
Description
Cost
 Advantages
 Disadvantages
SEA WALL
Concrete or rock barrier placed at top of beach or base of cliffs
Recurved face to reflect waves back into sea
Usually 3-5m high
Upto £6 million per km
Effective at stopping sea
Often have walkways or promenade that people can walk upon
Can act as a barrier to flooding
Very expensive to create and maintain
Can be unsightly
Create a strong backwash, which will scour the beach or underneath the wall
GROYNES
Timber or rock built from coast out into sea
Trap sediment moved by LSD to enlarge beach
Beach acts as buffer to incoming waves, reducing their energy and therefore erosion
£10,000 each (every 200m)
Results in a bigger beach which can increase tourist potential
Not too expensive
Wider beach leads too added natural protection from flooding and further erosion
Problem is ‘shifted’ rather than solved
Starve beaches down drift of material, increasing erosion there; and increasing risk of flooding
Unnatural looking, rock ones in particular are very unattractive
ROCK ARMOUR
Piles of large boulders (resistant rock) at foot of cliff
Rocks force waves to break, reducing energy and therefore erosion
£1,000 to £4,000 per metre
Relatively cheap
Often used by fishermen, so adds interest to the coast
Rocks are from elsewhere, which leads to expensive transport costs
Can be moved during storms, so need to be replaced

18. How Can Coastlines be Managed? – Soft Engineering
Soft Engineering Approaches
Soft Engineering approaches try to fit in with the natural environment and coastal processes. They do not involve artificial structures. They are more environmentally and economically sustainable as they are unobtrusive and normally have low maintenance costs.
 Strategy
Description
Cost
 Advantages
 Disadvantages
BEACH NOURISHMENT
Adding more sand or shingle to a beach to make it wider
Sediment locally sourced to blend in with existing beach
Normally brought onshore by barge
Appox. £3,000 per metre
Relatively cheap and easy to maintain
Blends in with existing beach
Increases tourist potential due to larger beach
Larger beach reduces risk of flooding and erosion
Needs constant maintenance due to LSD moving material down drift
Can kill organisms on sea bed
DUNE REGENERATION
Sand dunes are effective barriers against the sea
They are fragile, so easily destroyed
Planting Marram Grass stabilises the dunes
Fences will keep people off
Approx. £2,000 per 100metres
Maintains a natural environment that attracts wildlife and tourists
Relatively cheap
Time-consuming
Relies on people responding to the fenced off areas
Can be damaged by storms
Protection is only limited to that area
MARSH CREATION (MANAGED RETREAT)
Involves allowing low-lying coastal areas to flood
The area can become a salt marsh
This provides a barrier to the sea
Dependant on value of land; arable land costs £5,000 to £10,000 per metre
Cheap in comparison to implementing and maintaining sea defences
Creates habitats for wildlife
Flooding and erosion reduced behind the marshland
Land will be lost
Farmers or landowners will need to be compensated
Farmers livelihood would be affected

19. COASTAL HABITAT – Saltfleetby - Formation
Key Facts and Figures
Saltfleetby – Theddlethorpe Dunes stretch 8km along the North Lincolnshire coastline
Habitats include a saltmarsh and a variety of dunes
It is a National Nature Reserve (NNR) and a Special Area for Conservation (SAC)
Natural Processes
The sand dunes we see today first began to form in the thirteenth century after some unusually large storms. The sea threw up shingle and strong winds blew sand to the back of the beach. This process continues today, creating new shingle ridges, dunes and saltmarsh.
Human Influence
In the 1930s the area was used as a bombing range by the Air Ministry. During WW2, the dunes were mined to defend against invasion. The bombing range was moved in 1973 and the area became a NNR.

20. COASTAL HABITAT – Saltfleetby – Saltmarsh
Plants and Insects
Cordgrass – this is a salt-tolerant plant (halophyte), meaning it can colonise the saltmarsh, trap sediment and begin the process of vegetation succession
Marram Grass – this plays a vital role in stabilising the dunes, its fibrous, matted roots bind the sand. Its glossy, rolled-up leaves protect it from drying out. Once the dunes are stable it allows other plants like mouse-eared hawkweed and bird’s foot-trefoil to become established. These attract bees and butterflies. The smaller insects are hunted by dragonflies and robber-flies that patrol the dunes
Characteristics
Saltmarshes start as an accumulation of mud and silt in a sheltered part of the coastline
Over time, more deposition allows the mud to break the surface and form mudflats.
Salt-tolerant plants begin to colonise – these are known as pioneer plants.
As sediment is trapped by plants and they decay, the mud level begins to rise
This reduces the salt content and increases fertility of the soil, allowing new species to grow - this is vegetation succession.
Birds
The saltmarsh provides food and refuge for the many birds over winter. Ringed plover and Sanderling eat the small sandhoppers and shellfish found at the sea’s edge, while Curlew probe the mud for lugworms, Brent geese graze the saltmarsh grass and flocks of Twite and Snow bunting feast on the seeds of the saltmarsh plants.

21. COASTAL HABITAT – Saltfleetby - Management
Conservation and Sustainable use
The area is conserved to preserve its natural habitat; but it still able to be used sustainably. The reserve is managed by Natural England in partnership with the Lincolnshire Wildlife Trust and the Ministry of Defence.
Sustainable Use
Before the area became an NNR parts of the sand dunes were used to graze cattle by local farmers. During autumn and winter, a small number of cattle graze in the fenced enclosures.
Natural England run a range of free guided walks and activities from May to September each year.
The area is available for dog walking, but dogs must be kept on a lead to reduce the risk of damage
Conservation
Some areas are cleaned out to remove excessive sand and vegetation to provide suitable conditions for the wildlife. The NNR contains a significant population of Sea buckthorn and many areas are left for it to remain. However it is an invasive species and can easily dominate areas of the more finer examples of vegetation found growing in the dunes. Therefore some areas are cleared of the shrub, especially where it occurs in the newer dune system

22. Coastal Management -New Forest Coastline
Pressures on the Coastline
The New Forest District Council is responsible for this stretch of coastline, and split it into 3 key areas
3. Southampton Water
This area is developed, either for industry – such as the Fawley oil refinery and powerstation – or for housing – such as Hythe and Calshot. The remaining area are of great nature conservation value.; however these are at risk from water pollution caused by the industry.
1. Christchurch Bay
The area has narrow shingle beaches; sand and clay cliffs which are subject to high rates of erosion (60m since 1971)
Built up areas between Barton and Milford is at risk of landslips and mudflow after heavy rain.
Hurst spit is at risk of erosion due to being breached during heavy storms
2. Western Solent
The area has extensive coastal marshes with considerable wildlife value. It is low-lying so is at risk of flood during high tide or storms.

23. Coastal Management -New Forest Coastline
Management of the Coastline
Coastal erosion needs to be managed, but the council need to decide whether it is worth protecting the area with sea defences, this is known as Cost-benefit analysis
1. Christchurch Bay
They have built a concrete sea wall and groynes by Highcliffe and Milford-on-Sea.
These are hard engineering strategies, that are unattractive and unsustainable. They need constant maintenance.
Recent approaches are to work with nature, such as rock armour at Barton on Sea
Hurst spit is being breached regularly, so it could be better to let nature take its course, rather than introduce sea defences
3. Southampton Water
This area has one of the 3 Nature Reserves and a bird sanctuary, which have been put in place to protect wildlife
These encourage sustainable tourism into the area, and create a feature that will be available for future generations
2. Western Solent
Some of the low-lying areas around Lymington have been protected by dykes and floodwalls to reduce flood risk
Opinion is growing in favour of allowing coastal areas to flood, preserving the natural habitat – even if it puts buildings at risk

24. Rising Sea Levels - How
Increases in the atmospheric concentrations of the greenhouse gases (carbon dioxide, methane,
nitrous oxide and chlorofluorocarbons) is expected to result in substantial global-scale warming in the future. In response to this warming, global mean sea level will change, due to two main reasons.
1. Thermal Expansion
As oceans warm, its density decreases, which in turn increases the volume of water
2. Melting Ice
Global warming is causing Ice Caps (Ice covering land); glaciers and snow to melt.
This water eventually runs to the sea, increasing the overall volume of water in the sea
This is not the case for icebergs, as they displace the water, meaning there is no gain in water volume.

25. Rising Sea Levels - Maldives
The Maldives are a maximum of 2.4m above sea level, putting them at great risk from sea level rise. There will be a variety of impacts
Social
Houses would be damaged, severe floods could make entire communities homeless
There would be a loss of freshwater, meaning they would have to rely on rainwater or create expensive desalination plants
Political
They have to borrow money for defences – they borrowed $60 million from Japan
They have pledged to become carbon neutral, but if other countries don’t do the same, the Maldives will still be at great risk
They would need to consider mass evacuation, and are considering buying land from other countries before the islands become uninhabitable.
Environmental
Sea water would increase erosion, meaning beaches were lost, destroying habitats and increasing effects of flooding
Soil is shallow on most islands, rising sea levels could wash this away, meaning plants would be unable to grow
Economic
Tourism accounts for 28% of the Maldives economy – losing land to sea will reduce the number of visitors
Fishing is the second largest industry, with farming not being possible here, they require the income to buy exports of food from elsewhere

26. “Helping You on Every Step of Your GCSE Geography Adventure”
Glossary
Key Term
Definition
Abrasion (Corrasion)
Erosion caused by the rubbing and scouring effect of material carried by waves
Attrition
Erosion caused when rocks and boulders, transported by waves, bump into each other and break up into smaller pieces
Backwash
the movement of water down a beach to the sea
Biological Weathering
Weathering that involves the break down or degradation of rock by living organisms
Chemical Weathering
Weathering that involves a chemical change taking place
Constructive Wave
A powerful wave with a strong swash that surges up a beach
Corrosion (solution)
Erosion caused by acids in waves dissolving rocks by chemical action
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27. “Helping You on Every Step of Your GCSE Geography Adventure”
Glossary
Key Term
Definition
Crest
The top of a wave
Destructive Wave
A wave that crashes down onto a beach and has a powerful backwash
Fetch
distance wind has travelled over open water to create waves
Freeze-thaw Weathering
A process of physical weathering by which rock disintegrates due to water in cracks repeatedly freezing and thawing
Hard Engineering
Building artificial structures such as sea walls aimed at controlling natural processes
Hydraulic Power
Erosion caused by the sheer force of water breaking off small pieces of rock
Longshore Drift
The movement of material along a coast by breaking waves
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28. “Helping You on Every Step of Your GCSE Geography Adventure”
Glossary
Key Term
Definition
Managed Retreat
Allowing controlled flooding of low-lying coastal areas or cliff collapse in areas where the value of land is low
Mass Movement
The downhill movement of weathered material under gravity
Mechanical Weathering
a process of weathering which results in smaller pieces of the same rock material being produced.
Pioneer Plant
a species or community of plant(s) that is first to colonise a previously barren area.
Prevailing Wind
The direction from which the wind usually blows
Saltation
A process of transportation in which small particles bounce along the bed in a ‘leap-frog’ action
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29. “Helping You on Every Step of Your GCSE Geography Adventure”
Glossary
Key Term
Definition
Soft Engineering
A sustainable approach to managing the coast without using artificial structures
Solution
A process of transportation in which dissolved particles are carried in the water
Suspension
A process of transportation in which material is picked up and carried along with the water itself
Swash
the running of water up a beach under the momentum of a breaking wave
Traction
A process of transportation in which material is rolled along the bed
Vegetation Succession
A sequence of vegetation species colonising an environment
Weathering
The breakdown of rocks by either mechanical processes or chemical changes
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