AQA A GCSE Revision: The Coastal Zone
PART A: THE COAST IS SHAPED BY WEATHERING, MASS MOVEMENT, EROSION, TRANSPORTATION AND
DEPOSITION
1. What are the different types of waves that
operate at the coast?
Destructive Waves operate in storm conditions and
are about 5 or 6 metres high. The SWASH is weak and
the BACKWASH is strong and there is A LOT OF
EROSION. The FREQUENCY is also high, which means
there are more hitting the beach in a minute than
constructive waves.
Constructive Waves operate in calm weather and are
about a metre high. The SWASH is strong and there is
weak BACKWASH as the water percolates through the
beach sediment. Erosion is LIMITED. They’re involved
with the TRANSPORT and DEPOSITION of material
creating depositional landforms (beaches, bars etc.).
2. What will determine how large a wave will be?
i.
The fetch – how far the wave has come from
ii.
How strong the wind is
iii.
How long the wind has blown for
3. But how do the waves actually shape the coastline? This is due to EROSION, TRANSPORTATION & DEPOSITION.
Erosion is destructive waves wearing away the coastline. It happens when the waves are packed with energy. Erosion
can create landforms but eventually wear them away. The sea erodes the coast in four ways (these are the
PROCESSES OF EROSION)
I.
II.
III.
IV.
HYDRAULIC ACTION/ POWER - water crashes against the cliffs/rocks, and the air and water is trapped and
compressed in cracks. When the sea moves away again the air expands explosively weakening the rocks,
enlarging the cracks and breaking pieces off.
ABRASION (sometimes known as CORRASION) - is very effective and is caused by broken rock fragments
battering the land, cliffs etc. and breaking off other pieces of rock. Operates like ‘sandpaper’.
ATTRITION - occurs when rock fragments collide into smaller and get worn down into smoother and smaller
pebbles.
SOLUTION - involves chemical action of sea on rock. If the rock is limestone, it dissolves in the sea-watersome sea salts can also react with certain rocks and cause them disintegrate.
4.
Once the waves have eroded sediment how is it
transported?
Transport along the coast is when waves move material
across a beach. This is called LONGSHORE DRIFT.

Longshore drift happens when waves break at an OBLIQUE angle to the shore (not right angles) due to the
prevailing wind.

This means that each wave pushes
material along the beach a bit more.
(swash carries the material up the
beach at an angle and the backwash
drags the material down the beach at
right angles.)

Many depositional features such as
spits are formed by this process.
5. What other named processes of
transport are there?
6. What happens once the sea has finished transporting the sediment? DEPOSITION. This is the dumping of
eroded material on the land by constructive waves. It happens when the waves have less energy. Deposition
creates a variety of landforms, which are discussed later.
7. What other processes can shape the coastline?
WEATHERING! This is the breakdown of rock in situ (i.e. the stone doesn’t move). This
can happen due to Mechanical Weathering or Chemical Weathering:
Mechanical Weathering: includes freeze-thaw. Temperatures drop below freezing at
night and then rise during the day. As a result, any water in the cracks freezes and
expands and then thaws. Over time the expansion when the water turns to ice will
break the rocks apart.
Chemical Weathering: This includes solution. Water reacts with the calcium
carbonate in rocks like limestone and chalk. The rocks are dissolved and are washed
away.
8. What is ‘mass movement’?
The waves and the other processes discussed above can result in ‘mass movements’ on cliffs. There are two main
types:


Sliding – large chunks of rock slide down the slope
quickly without warning.
Slumping – common where cliffs are made of clay. The
clay becomes saturated during heavy rainfall and
oozes down towards the sea as part of a mud or debris
flow (more on this later in the Christchuch Bay case
study.
PART B: DISTINCTIVE LANDFORMS RESULT FROM DIFFERENT
PROCESSES
9. What are the landforms created by erosion?
WAVE-CUT PLATFORM - Waves erode rocks along the
shoreline by hydraulic action, abrasion and corrosion. A notch
is slowly formed at the high water mark which may develop into a cave. Rock above
the notch becomes unstable with nothing to support it, and it collapses. The
coastline (cliffs) can retreat over many years and a WAVE-CUT PLATFORM forms as
this process continues as only the base of the cliffs are left as the cliffs recedes.
HEADLANDS AND BAYS - If there are alternate bands of hard and softer rock in the
coastline, the harder rocks take longer to erode than the softer rocks- because the
sea has less effect. The hard rock will be left jutting out forming one or more
HEADLANDS, usually with cliffs. The softer rock will be eroded to form BAYS, the
erosion means the bays will usually slope more gently inland, creating room for a
BEACH TO FORM. Can you work out where the hard and soft rocks are found on this
map of the coast at Swanage in Dorset?
CAVES, ARCHES AND STACKS - A
crack in a headland can be erodedwave energy is usually strong there
because the headland juts out. This
forms one or more wave cut
notches/caves. Further erosion
enlarges the cave and it breaks
through the headland forming an
ARCH. The roof of the arch is often
unstable and eventually collapses
leaving a STACK or SERIES OF
STACKS. Areas with limestone or
chalk geology are prone to this kind
of erosion. MAKE SURE YOU REFER
TO ACTUAL NAMED PROCESSES
HERE.
10.
An example you
could use is
Durdle Door in
Dorset for an
arch
What are the landforms of deposition?
BEACHES - Deposition forms BEACHES. Depositional landforms are most common on
lowland coasts, beaches are the most common depositional landform. Beaches are
accumulations of sand and shingle deposited by waves and currents. The sediment comes
from cliff erosion but most is brought down to the coast by rivers. They can be SWASH
ALIGNED or DRIFT ALIGNED:

Swash Aligned beaches are where waves approach parallel to the shore and break
with swash moving directly up the beach and the backwash returning directly back. These form wide beaches
with an even shoreline. Ridges tend to form on beaches such as these called berms.
Example: Chesil Beach, Dorset.

Drift aligned beaches form when waves approach the beach at an angle resulting
in a swash moving diagonally up the beach and the backwash returning through gravity.
These movements create longshore drift (diagram on the previous page). These beaches
have an uneven profile- especially when groynes have been used to slow the longshore
drift. Example: West Wittering, West Sussex.
In terms of the shapes of the beach, the types of wave that have hit the beach will determine their profile. Look at
the start of this revision guide to see the different profiles. Sand beaches tend to be shallower than pebble beaches.
SPITS - Deposition also creates SPITS (East Head
Spit!!)
 Spits are beaches joined to the coast at one
end.
 At their seaward end shingle ridges form a
series of recurves or hooks.
 Spits often develop across river mouths or
where the direction of the coastline changes
abruptly.
 Spits form by a process called LONGSHORE
DRIFT (referred to earlier)
 Tucked away behind spits are quiet backwaters
that waves cannot reach, where tidal currents deposit fine silt and
build up MUDFLATS and SALT MARSHES.
BARS - Deposition also creates BARS. Bars take spits one stage further
and actually extends further and join up to another headland. This is
able to happen due to the lack of a strong river current that would
wash the sediment away like in the tidal race of a spit. A good example
of this is Loe Bar in Cornwall or Slapton Sands in Devon (pictures left).
If a spit extends and joins up with an island then this is called a
TOMBOLO. The best example of this is Chesil Bach joining to the Isle of
Portland in Dorset.
PART C: RISING SEA LEVEL WILL HAVE IMPORTANT
CONSEQUENCES FOR PEOPLE LIVING IN THE COASTAL
ZONE
11. Why are sea levels rising?
The belief is that global warming is causing sea levels to
rise. The heat is causing the ice caps to melt, which is
releasing water into the oceans. In addition, the extra
heat can cause thermal expansion of the sea too,
making it higher. Estimates suggest that levels could rise
between 30 - 140cm by the end of this century.
12. What case study of a location at risk of sea level
rise could be used?
The Maldives, shown on the map on the right, is a
collection of very low-lying islands. The highest point is
only 2.4 metres above sea level. The beautiful landscape
and white sandy beaches has resulted in 30% of the
country’s GDP being created by tourism.
The table on the next page shows the various
consequences of coastal flooding on the Maldives.
Economic
Social


Rising sea
levels could
end the tourist
industry


Traditional way of
life lost
Homes flooded
and land lost
‘Environmental
refugees’
Environmental


Coral reefs will die as
the water gets deeper
The ecosystems
associated with reefs
will be lost
Political


The whole country could
disappear!
Political tension between the
polluters and the Maldives – the
Maldives are suffering, but they
are not to blame for global
warming
PART D: COASTAL EROSION CAN LEAD TO CLIFF COLLAPSES. THIS CAUSES
PROBLEMS FOR PEOPLE AND THE ENVIRONMENT
13. What are the differences between ‘hard’ and ‘soft’ coastlines?
 A hard coastline is one made from solid rock - e.g. chalk, limestone or granite.
These are resistant to erosion and produce steep vertical cliffs like those found
around Swanage, Lulworth Cove and Durdle Door (Isle of Purbeck). Soft rock
coastlines consist of clays, sands and gravels and therefore far less resistant to
erosion. Crucially, these are also affected by weathering processes and slope
processes. Sock rock coasts become unstable when wet as their structure is not
strong- slumping often results.
 Hard rock cliffs will have a slow rate of recession and will tend to maintain a
vertical profile due to their strength. A wave cut notch can form at the base and
eventually, the rock above will fall, but the cliff will stay vertical.
 Soft rock cliffs have a fast rate of recession as they are weak and are attacked
by the waves, but also by sub-aerial (weathering) processes.
At Barton-on-Sea in Hampshire, rates of cliff recession are about 1 metre a
year! Alomng the East coast of England, some places are losing 8-10 metres a
year.
14. What other factors can influence rates of cliff recession other than the physical factors?
People build in inappropriate places! They disregard the geology and build on soft rock cliffs. Often, people would
want to build as near to the cliff edge as possible to gain spectacular views. However, the extra pressure of building
such a large and heavy structure on the cliffs (especially if made from sands and clays) can increase the chances of
cliff collapse.
15. What case study can be used for cliff collapse?
Christchurch Bay – see
map on the left.
Look at the map and
work out why Bartonon-Sea is susceptible to
coastal erosion.
Christchurch Bay is 16km long and parts are exposed to waves with a fetch of 3000km for the Atlantic. The area is
densely populated with a number of towns situated along it. Tourism is important to this area, so collapsing cliffs are
a major issue.
Why are the cliffs collapsing?
 Marine processes: The base of the cliffs are being attacked by the
waves (hydraulic action and abrasion). The large fetch results in
powerful, destructive waves.
 Sub-aerial processes: Weathering is weakening the rock and then
mass movements (slumping and rock fall) is leading to collapse
 Geology: Permeable sand lies on top of impermeable clay. During
heavy rain the water collects above the impermeable clay and the
sand becomes too heavy and collapses. The diagram on the right
explains this.
 Human activity: Extensive building along the cliff top has
resulted in too much weight on the soft cliffs and this has
promoted collapse.
 On the previous page I have circled a large groyne that was built
in 1938 to protect Hengistbury Head. Unfortunately, this has
prevented sediment from reaching the beaches along
Christchurch Bay, which has promoted further erosion.
What are the impacts of cliff collapse at Barton-on-Sea?
Social




Loss of homes

House values go down – 
people can’t move
House
insurance
very
expensive
Dangerous to walk on the
cliff tops
Economic
Roads under threat

Tourists may not visit 
(coastal protection works
look ugly?) Dangerous? This
impacts on local businesses
(taxis, cafes, hotels etc.)
Environmental
Cliff collapse looks unattractive
Cliff collapse exposes different rocks and
fossils – interesting to scientific
community. For example, the cliffs at
Naish Farm holiday village are being
allowed to erode for this reason as they are
a Site of Special Scientific Interest (SSI)
They have managed the cliffs at Barton-on-Sea, but they still continue to recede.
PART E: THERE IS DISCUSSION ABOUT HOW THE COAST SHOULD BE MANAGED. THERE IS DEBATE ABOUT THE
COSTS AND BENEFITS OF ‘HARD’ AND ‘SOFT’ ENGINEERING
16. Who manages the coast?
DEFRA (Department for Environment, Food and Rural Affairs) is the government department responsible for coastal
defence. The Environment Agency and local councils decide on how best to spend the money and protect the
coastline.
17. How is the coastline actually managed?
I don’t mean the actually methods employed like sea wall etc. What I mean is the general decisions about where to
protect (or not) and roughly what types of measures should be employed. As was discussed in Q16 above, local
councils and government work together and they formulate a plan
called a ‘Shoreline Management Plan’ or ‘SMP’.
Each SMP (an example is shown on the right) may propose
management of the sub-cell in a number of ways:




Hold the line - maintain the existing coastline by building
defences
Advance the line - build new defences seaward of the
existing defences
Managed retreat - allow the land to flood, and construct a
new line of defences landward of the existing coastline
Do nothing - allow natural processes to shape the land
18. How are coastlines actually protected?
Planners can use ‘hard’ strategies or ‘soft’
strategies.
 Hard management: physical structures
constructed to stop erosion by the waves.
 Soft management: working with nature
rather than against it. For example, beach
nourishment – no physical structures built.
19. What hard management strategies are used?
The diagrams below show the main options
employed. You need to know about sea walls,
groynes and rock armour.
20. How do these strategies work?
The table on the next page summarises the
information about the various hard strategies.
21. Hard strategies are very effective; surely everyone is in favour of them?
Not so! Examine the table below.
In favour


Local people with homes in 
danger

Local tourist businesses with
caravans and hotels at risk (but if 
the structures are ugly will that
not scare tourists away?!)
Not in favour
Local taxpayers who don’t live next to the coast (why should they pay?!)
Environmentalists – fear that habitats and natural beauty will be
affected
People living downdrift of the defences could be starved of sediment
(like the people at Barton when the 1938 groyne was built at
Hengistbury Head) and lose their beach
22. What soft management strategies
are used?
Soft management has become more
popular over the years and many
people now feel that this approach is
more sustainable and a more effective
way of managing the coast.
Soft management tends to be less
expensive, will last longer and is more
environmentally friendly than hard
management methods.
The table on the right discusses these
approaches further.
A CASE STUDY OF HARD AND SOFT
MANAGEMENT IS WEST WITTERING BEACH AND EAST HEAD SPIT – THIS CAN BE USED FOR THIS PART OF THE
SPECIFICATION, BUT ALSO THE FINAL PART DISCUSSED ON THE NEXT PAGE. THE MEDMERRY MANAGED RETREAT
SCHEME SHOULD ALSO BE REVISED TOO.
PART F: COASTAL AREAS PROVIDE A UNIQUE ENVIRONMENT AND HABITAT. THERE IS NEED FOR CONSERVATION
AND THIS LEADS TO CONFLICT WITH OTHER LAND USES
23. A case study of a coastal habitat (also use for hard and soft management!!)
East Head
Sea defences have interrupted the
natural coastal processes in the area
for the last 200 years
In the 1960s and 1970s the narrow
beach at the Hinge was breached
during high tides/ severe storms and
this was again threatened in 2004.
This was deemed to be unacceptable as
this would change currents at the
entrance of Chichester Harbour. The
cost of which would be hard to imagine
as the sailing industry in the area is
worth millions of pounds
In 2005 a rock berm was placed at the
Hinge. Gabion cages and wooden
groynes have also been employed.
There are even the remains of a wave
revetment at ‘The Hinge’ of the spit.
(HARD MANAGEMENT)
In 2005 and again in 2009, huge
amounts of sand (15,000 cubic metres)
was taken from the northern end of
the spit and placed at the narrow point
of the spit. (SOFT MANAGEMENT)
Marram grass was planted to stabilise
the feature. Psychological barriers were
also constructed to encourage people
not to go on the newly created sand
dunes. (SOFT MANAGEMENT)
Similar barriers were also used to rope
off the breeding area for the Ringed
Plovers and also the Silver Spiny Digger
Wasp. (SOFT MANAGEMENT)
You probably have an annotated
map in your books with this
information?
Conflict at East Head
 The sand dunes are fragile and don’t react well to humans!
 Too many tourists can bring litter and fire hazards
 East Head is a habitat for many rare species – i.e. The Digger
Wasps and Ringed Plover
 The beach can become very crowded
 Visitors need somewhere to park, plus other facilities like
toilets and paths
 Coastal erosion
Solutions at East Head













Marram grass planted
Dunes fenced off to prevent trampling
Shop and café placed far away from the spit and bins provided
Boardwalks used on the spit to prevent trampling
Information signs educate people about the environment
Area roped off for the Digger Wasps
Area roped off for the Ringed Plover
Car parking charges helped fund the protection of the beach
and spit
Groynes
Gabions
Toilets provided
Beach recycling (2005 and 2008)
Rock armour/ rip rap (2004)
ALL THESE THINGS ARE DESIGNED TO MAKE USE OF EAST
HEAD SUSTAINABLE
24. An example of managed retreat – Medmerry
Scheme, West Sussex.
East Head is just to the NW of Medmerry.
Medmerry Managed Retreat near Selsey






Low land near Selsey under constant threat. Low
value farmland – why bother protecting this?
Decision made to punch a hole in the defences and
build an earth wall inland. The sea flooded the land
and a salt marsh has been created. Great for wildlife!
Increased flood protection for 300 homes, the
sewage treatment works and the main road into Selsey.
Finished November 2013
10km of paths created
£28 million cost
Other useful sites:
http://www.s-cool.co.uk/gcse/geography/coasts
http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/