1.1 Coastal processes produce landforms
Types of wave: destructive and constructive
Destructive
Carry out erosion
Tall
Powerful
High frequency
Backwash greater than the swash
Take sediment from beach to sea
Constructive
Small
Weak
Low frequency
Carry out deposition
Swash is greater than the backwash
Sediment is pushed up the beach
The impact of weathering, erosion and mass movement on the coast: cliffs and wave-cut
platforms, headlands and bays, caves, arches, stacks and stumps.
Types of coastal weathering:
 Physical Weathering – When changes in temperature or rainfall cause the rock to weaken.
 Acid rain – If the air is polluted, it can be very acidic. When rain falls on rocks it reacts with
the minerals causing them to dissolve, and the rock to decay.
 Biological weathering – Roots of plants, and burrowing animals, can push into cracks in a
rock face and cause the rock to split.
Types of wave erosion:
 Hydraulic action - results from the force of the wave hitting the cliffs, often forcing air
pockets into cracks and crevices.
 Abrasion - caused by waves picking up stones and hurling them at the cliffs.
 Attrition – any material carried by the waves will become rounder and smaller over time as
it collides with other suspended particles.
 Corrosion – the dissolving of rocks and minerals by sea water
Types of coastal mass movement:
 Rock fall – fragments of weathered rock fall from a cliff under
gravity and collect at the base.
 Slumping – happens when the bottom of a cliff is eroded by
waves. The cliff slides downwards, often triggered by saturation
due to rain, which both ‘lubricates’ the rock and makes it heavier.
Landforms resulting from weathering, erosion and mass movement:
Cliffs and wave cut platforms
1. In most cliffs are lines of weakness (cracks), sometimes these run horizontally (bedding
planes).
2. Abrasion and hydraulic action erode the beddings planes creating a ‘wave cut notch’.
3. As the notch grows the top of the cliff is undercut and becomes unstable. Weathering
weakens it further.
4. Evetnually the top of the cliff collapses.
5. As there was little erosion beneath the low tide mark, a flat shelf of rock known as a ‘wave
cut platform’ is left.
Headlands and Bays
Headlands and bays form where the coastline is made of different types of rock. The weaker rock is
eroded more easily, leading to the creation of bays. The areas of more resistant rock are only eroded
slowly leaving headlands.
Caves, arches, stacks and stumps
1. Cliffs are often faulted (cracked)
2. Abrasion and hydraulic action erode the crack, enlarging it into a cave
3. The cave is widened and deepened by further erosion
4. If the sea cuts the whole way through the headland an arch is formed
5. Continued erosion will cause the arch to grow in size, eventually the roof of the arch will
become too heavy and will collapse, leaving a stack
6. Over time the stack is eroded at the base and collapses, forming a stump.
The process and impact of longshore drift on the coastline.
When waves approach the shore at an angle, due to the direction of the prevailing wind, their
swash pushes beach material up the beach at the same angle. Backwash then drags the
material back down the beach at a 90⁰, due to gravity. This produces a zig-zag movement of
sediment along the beach (as shown above).
The formation of beaches, spits and bars.
Beaches - Constructive waves deposit sediment on the coastline and lead to the formation of a beach.
This is especially the case on coastlines that are sheltered from wind and waves, such as in a bay.
Spits - Longshore drift carries sand along the beach. If the
coastline suddenly changes direction, the beach material
is deposited, builds up to form a sand bank known as a
‘spit’. The end of the spit is often curved by strong winds
and waves. Behind the site is an area of calm water in
which
salt
marshes
often
form.
Continued deposition and plant growth can turn the
marsh into new land.
Bar – A spit which stretches across an entire bay.
Tombolo – A spit which joins the coastline to an Island.
Practice Questions
1. What is meant by the term swash? (2 marks)
2. Give 3 features of a destructive wave. (3 marks)
3. Outline the process of longshore drift. (3 marks)
4. Explain how the sea can erode the coastline. (4 marks)
5. Using diagrams, explain how stacks form. (6 marks) (3 SPAG)
1.2 Coastal processes
Types of wave: destructive and constructive
Destructive
Carry out erosion
Arrive quickly
Tall
Powerful
High frequency
Backwash greater than the swash
Take sediment from beach to sea
Constructive
Small
Weak
Low frequency
Carry out deposition
Swash is greater than the backwash
Sediment is pushed up the beach
The impact of weathering, erosion and mass movement on the coast: cliffs and wave-cut
platforms, headlands and bays, caves, arches, stacks and stumps.
Types of coastal weathering:



Salt crystal growth – When spray from waves lands on rocks, the water can evaporate
leaving the salt behind. Salt crystals grow and create stresses in the rock, causing it to break
into small fragments
Acid rain – If the air is polluted, it can be very acidic. When rain falls on rocks it reacts with
the minerals causing them to dissolve, and the rock to decay.
Biological weathering – Roots of vegetation can grow into cracks in a rock and split the rock
apart.
Types of wave erosion:
 Hydraulic action - results from the force of the wave hitting the cliffs, often forcing air
pockets into cracks and crevices.
 Abrasion - caused by waves picking up stones and hurling them at the cliffs.
 Attrition – any material carried by the waves will become rounder and smaller over time as
it collides with other suspended particles.
 Corrosion – the dissolving of rocks and minerals by sea water
Types of coastal mass movement:
 Rock fall – fragments of weathered rock fall from a cliff under gravity
and collect at the base.
 Slumping – happens when the bottom of a cliff is eroded by waves.
The cliff slides downwards, often triggered by saturation due to rain,
which both ‘lubricates’ the rock and makes it heavier.
Landforms resulting from weathering, erosion and mass movement:
Cliffs and wave cut platforms
6. Horizontal lines of weakness (known as bedding planes) form in cliffs.
7. Abrasion and hydraulic action erode the bedding plane to form a ‘wave cut notch’.
The wave cut notch forms between the high and low tide marks at the base of the cliff.
8. Continued erosion makes the notch larger.
9. The top of the cliff is undercut by erosion and weakened through weathering. Eventually,
the cliff face becomes too unstable and collapses causing the cliff to ‘move back’.
10. As there was little erosion beneath the low tide mark, a flat shelf of rock known as a ‘wave
cut platform’ is left behind.
Headlands and Bays
The key to their formation is differences in geology. A discordant coastline occurs where
bands of differing rock types run perpendicular to the coast. The weaker rock is eroded more
easily, creating bays. The areas of more resistant rock are only eroded slowly, leaving them
sticking out into the sea, as headlands.
Caves, arches, stacks and stumps
7.
8.
9.
10.
11.
12.
13.
Vertical Lines of weakness (cracks / faults) occur in headlands
Abrasion and hydraulic action erode the faults, eventually forming a cave
The cave is widened and deepened by further erosion
The sea cuts the whole way through the headland – forming an arch
The sea erodes the arch at the base and widens it, leaving the roof unsupported.
The roof of the arch is weakened through weathering (physical and biological).
Eventually the arch roof becomes too unstable and collapses – part of the former cliff is
now isolated as a stack
14. Over time the stack is undercut and collapses – a stump is all that remains
15. Eventually, the stump too is eroded away and becomes beach material through attrition.
Coastal Transport – Longshore Drift
When waves approach the shore at an angle, due to the direction of the prevailing wind, their
swash pushes beach material up the beach at the same angle. Backwash then drags the
material back down the beach at a 90⁰, due to gravity. This produces a zig-zag movement of
sediment along the beach (as shown above). The smallest material, such as sand, is easiest to
carry and so ends up furthest along the beach. The heavier material, such as pebbles, are
harder to move and so do not travel as far in the same amount of time.
Depositional Landforms.
Beaches - Constructive waves deposit sediment on the coastline and lead to the formation of a
beach. This is especially the case on coastlines that are sheltered from wind and waves, such as in a
bay.
Spits - Longshore drift carries beach sediment along
the beach. When the coastline suddenly changes
direction, possibly due to a river estuary, the beach
material is deposited and builds up. Over time this
deposition leads to the formation of a sand bank that
extends the beach out into open water. This
sandbank is known as a ‘spit’. The end of the spit
often becomes curved by strong winds and waves.
The spit creates an area of calm water immediately
behind it. This leads to deposition. Plants begin to
grow - forming a salt marsh. The plants hold silt in
place and stabilize the landform. Continued
deposition and further plant growth turns the marsh
into land. This final stage is rarely reached as spits are
fragile and can be washed away during storms.
Bar - If longshore drift continues to extend the length of the spit, it may join back with the coastline
on the other side of an opening such as a bay. This results in the creation of a bar with a lagoon
behind.
Tombolo – Where a spit stretches to an island, joining it to the coastline, the feature created is
known as a Tombolo.
Practice Questions
1. Outline how coastal regions are eroded (3)
2. Compare constructive and destructive waves (3)
3. Describe the process of longshore drift (4)
4. Using annotated diagrams, explain how weathering and erosion lead to
the formation of wave-cut platforms are formed (6) (3 SPAG)
1.2 Coastal landforms are subject to change
Factors which affect the rate of cliff recession.
Why are some of Britain’s coastlines receding faster than others?
1) Fetch - Coasts that face a major ocean have a very long fetch and the winds are strong and
persistent. This produces destructive waves with high energy that can erode cliffs at a faster.
2) Rock Type (Geology) – Some rocks are more resistant to erosion than others affecting the
rate of erosion – e.g. Granite (hard); Clay (Soft).
3) Coastal Management – Coastal management can be used to slow rate of erosion.
The effects of cliff recession case study: Durlston Bay, Swanage
Between 1968 and 1988 the cliff receded 12 metres, ending up only 25 metres away from a number
of properties. Then in 2000/01 severe storms and high-energy waves led to a further retreat of 12
metres.
In Durlston Bay:
 Cliff front property can no longer get insurance.
 House prices in affected areas have collapsed.
 Electricity and photo cables have been re-routed to
avoid the collapse zone.
 Some roads are no longer passable.
 Sections of the coastline are no longer open to tourist.
Prediction and prevention of the effects of coastal flooding by forecasting, building design,
planning and education
In the UK, we are warned of coastal floods to enable us to take precautions:
 The Met Office predicts the likelihood of a coastal flood and
gives this information to the public through weather forecasts
online and on the television.
 On the Environment agency website there will be information
on the likelihood of a flood, identified through a system of
warning codes (shown right).
 There are also a number of websites run by the government
to give advice to the public in areas prone to flooding.


DEFRA (the Department for Environment, Food and Rural
Affairs) has the responsibility of deciding which areas of
the coastline are going to be defended against coastal
flooding. The Environment Agency then organises for the
defences to be built and maintained.
The Storm Tide Forecasting Service provides the
Environment Agency with forecasts of coastal flooding
which the Environment Agency then communicates to
the public via their website or phone line.
The effects of flooding can also be minimised by building design and control. Before houses can be
built the local authority has to give planning permission – this is not granted in flood risk areas unless
a risk assessment has been carried out.
Past Paper Questions:
1. Give two reasons why some coastlines are receding faster than others. (2)
2. Outline the impacts of a receding coastline on area you have studied. (3)
3. Describe how planning can reduce the damage caused coastal flooding. (3)
4. Explain how rock type can affect rates of coastal erosion. (4)
The types of hard and soft engineering used on the coastline of the UK and the advantages
and disadvantages of these techniques.
Hard Engineering
Rip-rap
Description
Large rocks placed in
front of the cliff.
COST- £300 per
person
Recurved seawall
Walls usually made of
concrete, more
modern ones have a
recurved face.
COST - £3000 per
metre
Groynes
Offshore reef
Revetments
Advantages
Dissipates wave
energy
Can be very cheap,
depending on the
rock type
Effective for many
years
Disadvantages
Can make the
beach
inaccessible to
tourists
Unattractive
Not effective in
storm
conditions
Reflects and
absorbs wave
energy
Very obvious –
make residents feel
safe
Effective for many
years
Usually made of wood, Prevents Longshore
stretch from the
drift
coastline to the sea
Keeps beach in
COST - £5000 each
place for the
tourist industry
Effective for many
years
Ugly
Expensive
Can cause wave
scouring if not
positioned
correctly
Enormous concrete
blocks and natural
boulders are sunk
offshore to alter wave
direction and dissipate
the energy of waves.
COST - £1,950 per m
May be
removed by
heavy storms
Difficult to
install
Slatted wooden or
concrete structures
built at the base of a
cliff
The waves break
further offshore
and therefore
reduce their
erosive power.
They allow the
build-up of sand
due to the
reduction in wave
energy
These absorb wave
energy through
slats and do not
interfere with
longshore drift
Becomes
difficult to walk
along the beach
Disrupt the
natural working
processes on
the beach
Regular
maintenance is
needed.
Expensive.
Soft Engineering
Beach Replenishment - The placing of sand and pebbles on a beach. COST - £5000 per 100m
 Looks natural
 Provides beach for tourists
 Dissipates wave energy
 Relatively Cheap
However…
 It may affect plant and animal life
 The scheme requires constant maintenance.
 Disruption for home-owners, large noisy
Lorries full of sand regularly replenish the
beach.
Cliff Regrading – The cliff is cut back and given a new gentle slope to stop it slumping
 May be covered in ecomatting to encourage vegetation growth
 Very natural – will encourage wildlife in the area
However…
 Not effective by itself will need other defences installed at cliff’s base
 Some homes on the cliff may have to be demolished
Managed retreat – Allowing the sea to gradually flood land or erode cliffs.
 Creates new habitats for plants and birds
 Little direct expense.
However
 Upsetting for landowners who lose land
How the coast is managed in a named location – Swanage and Durlston Bay
In Durlston Bay, several methods were used to protect cliffs from erosion and to safeguard
the buildings on the cliff top. The defences included:
 Regrading of the cliff
 Installing drainage to reduce mass movement
 Placing rip-rap
Swanage Bay needed different methods of defence:
 Sea wall
 Cliff regrading
 Groynes
 Beach replenishment
Practice Questions
1.
2.
3.
4.
Name two forms of hard engineering (2)
Give two advantages of using soft techniques to manage coastal retreat (2)
Outline how groynes reduce coastal erosion? (3)
For a named coastal area, explain the management measures used. (6)
1.2 Coastal landforms are subject to change
Differing rates of cliff recession.
Why are some of Britain’s coastlines receding faster than others?
4) Fetch - Coasts that face a major ocean (e.g. the SW coast of England), have a very long fetch
and the winds are strong and persistent. This produces destructive waves with high energy
that can erode cliffs at a faster rate than waves with a smaller fetch and less energy.
5) Rock Type (Geology) - The geology of South-West England is mainly granite, which is a very
resistant rock; making the actual rates of erosion very slow. Coastlines with a less resistant
rock type, such as clay, will erode much faster.
6) Coastal Management -The final factor that affects these rates is coastal management. If
coastal defences such as sea walls protect weak geology then rates of erosion will be much
slower. Granite boulders (rip rap) are often placed in front of weak cliffs to protect them.
The boulders absorb the energy of the waves protecting the cliff.
The effects of cliff recession: Durlston Bay, Swanage
Many houses, hotels and apartment blocks are built on cliff-tops to take advantage of the sea views.
Cliff recession has put these properties at risk of collapse into the sea. At present in the UK, loss of
property to cliff recession is not covered by home insurance policies.
In Durlston Bay:
 Between 1968 and 1988 the cliff receded 12 metres, ending up
only 25 metres away from the apartment block ‘Purbeck
Heights’.
 In 2000/01 severe storms and high-energy waves led to a
further retreat of 12 metres, putting many properties at risk.
These properties have become uninsurable and have crashed
in value.
 Durlston Country Park also lies on the cliff top and is home to
over 250 different species of birds, including Puffins and
Falcons that nest on the cliff. Their habitat and breeding is put
at risk by cliff recession.
 Some roads and utility networks (e.g. power cables) have had
to be re-route to prevent damage from future cliff collapse.
 Some section of the coastline have been sectioned off as they
present a danger to walkers and tourists. This has discouraged
some tourists from visiting the area.
Prediction and prevention of the effects of coastal flooding by forecasting, building design,
planning and education
In the UK, we are warned of coastal floods to enable us to take precautions:
 The Met Office predicts the likelihood of a coastal flood and gives this
information to the public through weather forecasts online and on the
television.
 On the Environment agency website there will be information on the
likelihood of a flood, identified through a system of warning codes
(shown right).
 There are also a number of websites run by the government to give
advice to the public in areas prone to flooding.


DEFRA (the Department for Environment, Food and Rural Affairs)
has the responsibility of deciding which areas of the coastline are
going to be defended against coastal flooding. The Environment
Agency then organises for the defences to be built and
maintained.
The Storm Tide Forecasting Service provides the Environment
Agency with forecasts of coastal flooding which the Environment
Agency then communicates to the public via their website or
phone line.
The effects of flooding can also be minimised by building design and control. Before houses can be
built the local authority has to give planning permission – this is not granted in flood risk areas unless
a risk assessment has been carried out.
Past Paper Questions:
1) Define the term ‘fetch’ (2 marks)
2) For an area you have studied, describe the impact of coastal retreat (4 marks)
3) Outline the actions taken in the UK to limit the damage caused by coastal flooding
(4 marks)
4) Examine why some coasts retreat faster than others (9 marks)(SPAG 4)
The types of hard and soft engineering used on the coastline of the UK and the advantages
and disadvantages of these techniques.
Hard Engineering
Rip-rap
Description
Large rocks placed in
front of the cliff.
COST- £300 per
person
Recurved seawall
Walls usually made of
concrete, more
modern ones have a
recurved face.
COST - £3000 per
metre
Groynes
Offshore reef
Revetments
Advantages
Dissipates wave
energy
Can be very cheap,
depending on the
rock type
Effective for many
years
Disadvantages
Can make the
beach
inaccessible to
tourists
Unattractive
Not effective in
storm
conditions
Reflects and
absorbs wave
energy
Very obvious –
make residents feel
safe
Effective for many
years
Usually made of wood, Prevents Longshore
stretch from the
drift
coastline to the sea
Keeps beach in
COST - £5000 each
place for the
tourist industry
Effective for many
years
Ugly
Expensive
Can cause wave
scouring if not
positioned
correctly
Enormous concrete
blocks and natural
boulders are sunk
offshore to alter wave
direction and dissipate
the energy of waves.
COST - £1,950 per m
May be
removed by
heavy storms
Difficult to
install
Slatted wooden or
concrete structures
built at the base of a
cliff
The waves break
further offshore
and therefore
reduce their
erosive power.
They allow the
build-up of sand
due to the
reduction in wave
energy
These absorb wave
energy through
slats and do not
interfere with
longshore drift
Becomes
difficult to walk
along the beach
Disrupt the
natural working
processes on
the beach
Regular
maintenance is
needed.
Expensive.
Soft Engineering
Beach Replenishment - The placing of sand and pebbles on a beach. COST - £5000 per 100m
 Looks natural
 Provides beach for tourists
 A beach is the best form of natural defence – it
dissipates wave energy
 Cheap
However…
 It may affect plant and animal life in the area
 The scheme requires constant maintenance. It can all
be washed away in as little as a year.
 Disruption for home-owners, large noisy Lorries full
of sand regularly replenish the beach.
Cliff regarding – The cliff is cut back and given a new gentle slope to stop it slumping
 May be covered in ecomatting to encourage vegetation growth
 Very natural – will encourage wildlife in the area
However…
 Not effective alone – need other defences at cliff base
 Some homes on the cliff may have to be demolished
Managed retreat – Allowing the sea to gradually flood land or erode cliffs.
 Creates new habitats for plants and birds
 Cheap
However
 Upsetting for landowners who lose land
 Difficult to estimate the extent of sea movement especially with rising sea levels.
How the coast is managed in a named location – Swanage and Durlston Bay
In Durlston Bay, several methods were used to protect cliffs from erosion and to safeguard the
buildings on the cliff top. Erosion mainly occurred at one particular point, where there was a major
weakness in the rock. The defences included:
 Regrading of the cliff
 Installing drainage – removing excess water, so that the slope was not as heavy or as well
lubricated after rain.
 Placing rip-rap
Swanage Bay needed different methods of defence, because the erosion occurred over a large
stretch of cliff rather than at one point. Homes and hotels on the cliff top needed protecting from
the danger of cliff collapse. The methods used were:
 Sea wall built in the 1920s and acted as a promenade for tourists as well as a wave barrier.
 Cliff regrading – a series of steps were made in the cliff to reduce slope angles
 Groynes, installed in the 1930s. 18 have recently been replaced.
 Beach replenishment – 90,000 cubed metres of sand was dredged from Studland Bay and
pumped onto the beach at Swanage.
 The cost of the recent beach replenishment and groyne replacement was around £2.2m.
Practice Questions
1. Outline how sea walls prevent coastal retreat (3)
2. Explain how groynes protect cliffs from erosion by the sea? (4)
3. What are the disadvantages associated with using hard engineering to manage coastal
retreat (3)
4. For a named area, describe the effects of coastal retreat (4)
5. using examples, explain how soft engineering can be used to manage coastal retreat (6)