Coastal Processes, Landforms and Issues
Key questions:
1. What natural processes are taking place at the coast?
2. How do these processes effect humans living by the coast?
3. How are coastal landforms created?
4. How do we make use of coastal landforms?
5. How can we manage coastal areas and landforms in a sustainable way?
6. How have coastal processes affected the Holderness coast and how have they been
managed?
Key vocabulary:
Erosion: the wearing away of the landscape.
Sustainable: capable of being maintained into the future for further
generations to enjoy.
Permeable rock: rock which allows water to soak through.
Impermeable rock: rock which does not allow water to soak through.
Processes and landforms of coastal erosion
There are four types of erosion which take place along the coastline. These are:
Hydraulic action – water crashes into lines
of weakness in the cliff, pushing air further
into the gap and forcing the rock apart.
Abrasion - when rocks within the water are
pushed into the cliff face by the force of the
waves and knock other pieces of rock off the
cliff.
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Attrition - when rocks within the water are moved about due to the
movement of the waves, they hit against each other knocking bits off and
becoming smaller and smaller, as well as more rounded.
Corrosion - when weak acid or salt within the sea water dissolves the rock on the side of the
cliff. Rocks such as chalk are particularly susceptible to this kind of erosion.
Erosion causes a number of coastal landforms; these landforms often attract many tourists:
Headlands and bays: Bays are areas of soft rock that have been eroded more quickly than
areas of hard rock which then stick out into the sea as headlands.
Crack: these are formed at weak spots within the rock.
Cave: as cracks eroded further they form caves.
Arch: If a cave is formed in a headland it may break through to the other side forming an
arch.
Stack: If the roof of an arch collapses it will form a stack.
Stump: As the waves attack the foot of the stack it will eventually topple over leaving only a
small short rock form called a stump.
Activity:
On the diagram below label the landforms of erosion.
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As cliffs are eroded they retreat further back into the land. Cliff retreat also leads to a
number of landforms being created such as wave-cut notches and platforms.
Softer areas or rock, such as bays, suffer from erosion (predominantly abrasion) from the
sea but also from above.
Permeable sand
based rocks
Wave attack
Abrasion
Impermeable clays
Direction
of slumping
As the waves attack from below so rain soaks into top permeable layers making them heavy
and unstable. These types of cliff are very unstable and dangerous to walk across.
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Processes and landforms of transportation and deposition
Long shore drift: this is the main type of transportation which takes place along the coast.
It takes place when the waves hit the beach at an angle, the swash (water from a wave
travelling up the beach) takes material up the beach at an angle and then the backwash
(water from a wave returning to the sea) takes the material back to the sea at a right angle
to the coast line due to gravity. Material is the moved in the direction that the waves hit the
beach at (normally the direction of the prevailing wind).
Deposition – this is when material which has been eroded and then transported is dropped by
the sea. It can build up into a number of different landforms.
Landforms of deposition are all formed due to the deposition of material like rocks and sand.
Spit: Spits form when long shore drift
carries material across a bay and to
the end of a headland. The material is
then deposited at the end of the
headland and as more and more is
deposited the sandy area starts to
stick out away from the headland. If a
spit forms at a river estuary the
movement of the river water travelling
to towards the sea will stop the spit
from protruding out too far.
Bar: If a spit forms from a headland and
there is no river there to stop the
deposition it is possible for the spit to
join two headlands together and cut the
bay and beach off from the sea. This is
called a bar.
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Tombolo: If a spit forms from a
headland with an island close by it could
join the island to the mainland. This is
called a tombolo.
Activities:
Use the aerial photograph below to
complete the activities.
1. On the map
draw an arrow to
show the
direction of long
shore drift and
circle the two
spits.
2. Explain how you decided on this as the direction of long shore drift.
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Coastal Management
People living on the coast are increasing vulnerable to coastal erosion. A variety of methods
have been put into place to reduce the impacts of coastal erosion.
Name of
management type
Sea wall
Description
Advantages
Disadvantages
A concrete wall built along
the back of a beach or on sea
front.
Effective at reflecting waves,
lasts a long time.
Expensive, ugly, reflects energy
does not absorb it, leads to erosion
of material in front of wall, can
prevent access to beach.
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Revetments
Large rock or concrete
boulders placed at back of
beach or on sea front.
Absorbs waves energy, lasts a
long time, effective.
Expensive, un-aesthetically
pleasing, can prevent access to
beach, dangerous to walk on.
Gabions
Small stones and rocks held
together in wire mesh placed
at back of beach or on sea
front.
Wooden or rock structures
which stick out into the sea
to prevent long shore drift
taking beach sand away.
Absorbs wave energy, cheaper
than other options, vegetation
can grow on them over time.
Doesn’t last a long time (small
stones are eroded within mesh),
Can prevent access to beach.
Very effective at stopping long
shore drift, wooden groynes
cheaper than other options,
help to keep the beach
benefitting tourism there.
Stops sand being transported down
the coast leading to more erosion
down the coast, sand will build up
at groyne and need to be redispersed.
Beach nourishment
Sand material is added to
making a larger beach to help
slow waves.
Soft engineering, helps create
large beach which encourages
tourism, material will benefit
areas down the coast as it is
transported there.
Needs to be regularly topped up as
sand it transported away through
LSD. Problems sourcing the sand.
Off shore reef
Tyres or rocks are placed in a
band off shore making the
water shallower and making
the waves break earlier.
Soft engineering, is using old
tyres can be cheaper option,
reefs attract fish and can be
used for diving, also means
waves hitting beach are
smaller and safer for bathers.
Shallow areas unsafe for some
shipping, if using tyres there is a
chance of them breaking off the
reef and being taken away into the
sea, makes waves smaller which
will stop surfing.
Planting vegetation
Grass is planted in sand
dunes to hold sand in place.
Soft engineering, cheaper
option, encourages wildlife
there.
Not appropriate for many areas,
prevents sand being transported by
LSD to other areas.
Managed retreat
Coastline is left to retreat
due to erosion but the area is
monitored for safety and
people evacuated from
danger zones.
Soft engineering, cheaper
option, doesn’t impact on
coast further down.
Loss of homes and businesses.
Buildings need to be removed
before cliff collapses.
Groynes
All of the above methods can be classified into hard and soft engineering.
Hard engineering are methods which try to prevent natural processes (e.g. erosion),
examples would include sea wall, revetments and gabions.
Soft engineering are methods which try to encourage natural processes (e.g. waves breaking
and slowing), examples include beach nourishment, planting vegetation and managed retreat.
Unfortunately most coastal management methods have severe impacts further down the
coastline. As less material is eroded of transportation is stopped to beaches further down
the coast are diminished. Beaches act as natural protection to the cliffs beyond, slowing the
waves down before they reach the cliff or stopping them from reaching the cliff all together.
Therefore as beaches are destroyed this leads to increased erosion at these places.
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Activities:
1. Name one type of soft engineering and explain the advantages and disadvantages of this as
a form of coastal management.
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2. Use the photo opposite to answer the
following.
a) What two forms of coastal
management are in place?
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b) Explain why the erosion has increased
on the East side of the photo.
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Extra c) Suggest another form of coastal management for the West side of the photo that
would not create an increase in erosion on the East side of the photo. Explain your choice.
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Coastal erosion, landforms and management on the Holderness Coast – Case Study
The Holderness Coast is located on the North-East coast of England; it is one of the fasted
eroding coastlines in Europe due to its soft geology.
The soft boulder clay that
makes up most of the area
is easily eroded and then
the material is transported
southwards due to long
shore drift. This has led to
the formation of Spurn
head at the mouth of the
Humber. Towards to
North of the coastline
Flamborough head is make
up of harder chalk as many
attractive landforms of
erosion are found here.
Chalk stack
Chalk arch at
at
Flamborough
Flamborough
Head
Head
Spurn head attracts a large number of tourists to this area; it is
one of the UK best examples of a spit being over three miles long.
The whole area is protected as a nature reserve (many rare
species living in the salt marshes behind) and the spit is part of
the UK Heritage coastline. It provides jobs in local cafes and
souvenir shops along with hotels. However it is under threat by
increasing coastal management further up the coastline. As
residential areas such as Mappleton are protected there is less
eroded material being transported to replenish the spit.
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Example of the impacts of Coastal Management: Mappleton
The village of Mappleton is greatly underthreat by coastal erosion along the coastline and by
1998, the main road running through the village was only 500m from the cliff top and in
places it is now only 50m. The village is under threat due to the easily eroded boulder clay
(glacial till) which makes up the cliff line. The area suffers from erosion rates of up to 2m
per year.
Protecting Mappleton - To reduce the amount of erosion threatening Mappleton, 2 rock
groynes were constructed in 1991 to encourage the build up of beach in front of Mappleton
by trapping longshore drift. This meant that that waves would break on the beach rather
than attacking the cliffs.
Problems for further down coast - Those living south of Mappleton village have experienced
the 'knock-on' effects of the coastal management.
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Exam Practice – 2007 and 2003
1. Study the photo below from the Great Ocean Road in Australia.
a) Explain how this coastal
landform was created. You may
use diagrams if you wish.
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b) Explain why tourists are attracted to coastal areas like the Great Ocean Road.
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2. a) What do you understand by the terms ‘erosion’ and ‘deposition’?
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b) Study the photograph below.
i) Draw an
outline map
of the area
and label
the
following on
it;
Salt marsh
Sand and
shingle
(3)
ii) Give one example of photo evidence that people have used this landform.
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3. CASE STUDY: Coastal landforms.
For a named coastal landform describe how the landform was created and explain how it is
being used and affected by people. Use diagrams if required.
Named coastal landform: __________________________________________________
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Flooding
Key questions:
1. How are floods caused?
2. What are the effects of flooding?
3. How can the risk of flooding be managed?
4. What were the causes and effects of the floods of the River Severn
in 2000 and how has it since been managed?
5. What were the causes and effects of the floods on the River Ganges in
1998 and how have it since been managed?
Key vocabulary:
Delta: A river formation at the mouth (where river meets the sea) of a
river where deposition causes new land to be formed.
Discharge: The amount of water flowing through a river, measured in
cubic metres per second (cumecs).
Groundwater flow: The flow of water through rocks.
Hydrograph: A graph showing the discharge of a river over time.
Causes of flooding
The main cause of flooding is high levels of rain fall over a short period of time.
Rock type can affect the chances of flooding. Areas with impermeable rocks will be more at
risk from flooding and the ground will not soak up the rain.
Urbanisation leads to more surfaces being made impermeable due to use of concrete. Water
runs off quickly into gutters and reaches rivers much quicker.
Vegetation cover will decrease the chances of flooding as the plants will take up the water
through their roots.
Tsunamis can cause devastating coastal flooding, tsunamis are caused by earthquakes which
happen at sea and create giant waves.
Strom surges also lead to coastal flooding. This is where a strong storm lifts up the sea
water and causes sea levels to rise temporarily.
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Deforestation means trees are cut down to create more farm land, this increases the risk of
flooding as there is less vegetation to take up the water.
Relief of the land; steep valley sides means rain water runs into the river in a short space of
time. The river does not have time to deal with such a large amount of water in a short space
of time.
Activity
1. Sort out the causes of flooding above into natural and human causes.
Natural
Human
Extra 2. Explain how climate change can lead to increasing frequencies of serious flooding.
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Flood hydrographs
Flood Hydrograph show how a river's discharge responds following a period of heavy rainfall.
On a hydrograph, the flood is shown as a peak above the base (normal) flow of the river.
River discharge does not respond immediately to rainfall inputs as only a little of the rainfall
will fall directly into the channel. The river will start to respond initially through inputs from
surface runoff (the fastest flow of water) and its discharge will later be supplemented
through inputs from throughflow and groundwater flow.
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Effects of flooding
Short term effects include:
Loss of life
Crop damage
Roads closed
Water
borne
diseases
spread
Businesses
forced to
shut
Electricity
cuts
Long term effects include:
People’s homes remain ruin
for many months
Lack of future investment in
area
House and business insurance
rises or is refused
Activity
Sort the effects above into economic and social. Create a key to show your categorisation.
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Flood prevention
Type of management
Advantages
Disadvantages
Damn – water is held back
against a damn wall and only
released when the river has the
capacity for it.
Can also be used to create
electricity. Very reliable at
reducing flooding.
Very expensive, prevents the deposit of
minerals from river into farm land,
flooding behind damn can lead to
settlements being lost, danger of damn
breaking.
Levees – banks built along the
side of the river to enlarge its
capacity.
Fairly cheap method.
Prevents water re-entering the river
when rain stops.
Tree planting – Trees are planted
to soak up excess water from
rain.
Fairly cheap method. Provides
more trees which gives habitats
and takes up CO2. Soft
engineering favoured by
environmentalists.
Takes time for trees to be established.
Can only soak up a finite amount of
water.
Dredging – material removed
from river channel to higher its
water capacity.
Simple way to increase the
amount of water a river can
carry.
Needs to be done regularly to keep
channel deep. Can lead to greater
flooding down steam as water arrives
there quicker.
Straightening / widening river
channels - river is made wider
and channels straighten.
Allows water to move quickly out
of urban areas where effects
from flooding would be high.
Can lead to greater flooding down steam
as water arrives there quicker.
Flood plain clearance – keeping
flood plains free from housing
and business so damage from
floods in minimal.
Soft engineering method. Allows
land at flood plain to be used for
parks and farm land.
Reduced land available for housing. Does
not stop the actual flood so can still be
dangerous to people in the area.
Sand bags – bags of sand handed
out to households at risk of
flooding, will hold back water
from seeping under doors.
Can be given out when needed.
Fairly cheap method. Can be
targeted to people at risk.
Not that effective in stopping water from
entering homes. Only a short term
solution.
Activity
1. Sort out above management strategies into hard and soft engineering options (review
meanings from coastal management if needed). Create a key to show your categories.
Extra 2. How are the water levels of the River Trent controlled (it is not one of the above!)?
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Flooding on the River Severn in 2000 – Case study
The River Severn begins in the Cambrian Mountains in
Wales and flows out through England and the Bristol
Channel. It is the longest river in Great Britain.
Some of the most serious effects of the 2000 floods
were felt in the tourist town of Bewdley.
Causes:

Highest levels of rainfall in over 270 years

Location in the West of the UK close to Wales
leads to high levels of rainfall all year round

river, further afield mostly farm land, little
Effects:

Insurance costs rise

140 homes flooded –damage
to buildings

Loss of income for the area
from tourism and
agriculture

Loss of personal belongings
for residents

Land use – urban land use on the banks of the
forest

Dredging ceased in the 1950s due to high costs

Climate change blamed for increase in stormy
weather conditions

Narrow river channel in Bewdley
Flood prevention:

Due to the effects of the flooding shown above the
government saw the need to put in flood defence
Transport links cut off
mechanisms.

The chosen method was a 2.7 metre high
demountable flood wall.

It acted in a similar way to levees, increasing the
amount of discharge the river could carry before if
would flood the outside areas.

Bewdley during
2000 and 2007
floods.
Go to the following web pages for
The wall was made demountable so it was not an
eyesore to tourists when there was no flood risk.

It can be erected in 24hours

It dramatically reduced the potential effects of
the high river levels in 2007. Without the wall the
town would have flooded severely again.
 The net benefits of the wall were calculated to be
more…
Flooding on the River Ganges 1998 – Case £0.6
studymillion following an initial cost benefit
http://www.geography.org.uk/resour
analysis.
ces/flooding/bewdley/whathappened
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Background
Between July and September 1998, Bangladesh
suffered one of its worse ever floods. Despite being
flooding being common in this country, the floods of
1998 were particularly severe resulting in over 1000
deaths and 30 million people being made homeless.
Physical causes
Effects

Over two thirds of the land was underwater
including Dhaka covered by 2m.
30 million made homeless with many more
damaged homes.
Official death toll of 1, 070. Deaths caused by;
drowning, contamination of water leading to
water board diseases e.g. cholera, lack of
access to medical care for non-flood related
conditions due to break down of transportation.
Food supplies severely affected as farm land
an crops are flooded.
Economy suffers as businesses and factories
are flooded, 20% drop in exports.
Transportation cut off in many areas leading to
relief efforts not being able to reach areas.





 Bangladesh is a low lying country with 70% of
its land at less than 1m above sea level and 80%
being on the floodplain of the Ganges and
Brahmaputra rivers.
 Bangladesh is set on the drainage basins of
the rivers Ganges and Brahmaputra and so is at risk
of both these rivers flooding.
 Bangladesh has a monsoon climate meaning
heavy annual rains which often result in the rivers
exceeding their carrying capacity.
 In spring melting snow from the Himalayas
further increases the amount of water in the two
rivers and the chance of flooding.
Human causes
 Population increase in Bangladesh, Nepal and
India has led to more deforestation.
 Deforestation in areas of Nepal and India
further upstream means that less water is intercepted
and more ends up in the rivers.
 Deforestation has also led to more erosion
upstream leading to silt being carried downstream.
This is then deposited in the channel later on
reducing the amount of water it can carry.
 Bangladesh is an LEDC and has high national
debt. It therefore has little money to spend on flood
defences and protection methods.
Short term response



International food aid.
Volunteers and aid agencies try to rebuild flood defences in case of further flooding.
Make shift medical centres set up.
Possible long term solutions





Creation of more levees (embankments which raise sides of river increasing its channel capacity.
Constructing flood protection shelters in higher land to shelter people and animals in times of emergency.
– 2003
Emergency flood warning systems and Exam
plans topractice
be put in place
and practiced annually.
Providing medical stores in villages.
Building flood proof storage shelters for food and emergency
supplies.
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1. Study the map and news item below.
Maximum and minimum discharge of the Parana River 1951-2001 (at Corrientes)
a) How did the maximum discharge of the Parana River change between 1951 and 2001?
Refer to figures in your answer.
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b) Choose two of the causes given for increased flooding in the news article. For each cause,
explain why it could increase flooding on the Parana River.
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c) Study the map below which shows the location of Resistencia.
i) What is being done to protect the town from flooding?
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ii) Suggest two other ways of protecting the town from flooding. Explain how each would
work. ________________________________________________________________
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2. Case study: A place where a serious flood has affected people and the environment.
Name a place where you have studied a serious flood. Describe how the flood affected
people and the environment. Explain what people could do or have done to prevent flooding
from affecting them in the future.
Named place: ___________________________________________________
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