This is for the 9696 Syllabus for A level Geography but I'm sure it applies to other courses too. Hope you find this useful. :)

2. Why do coastal landscapes
vary?
• Lithology (Rock Type): Hard rocks (granite + basalt) give rugged landscapes such as Giants
Causeway in N. Ireland, whereas Soft Rocks (sands + gravels) give low flat landscapes like the Nile
Delta.
• Geological Structure: concordant (Atlantic) or accordant (Pacific) coastlines occur where the
geological strata lie parallel to the coastline. Whereas, discordant (Atlantic-type) coastlines occur
where the geological strata are at right angles to the shoreline.
• Processes: Erosional landscapes contain many rapidly retreating cliffs, whereas areas of rapid
deposition contain many sand dunes and coastal flats.
• Sea Level changes: interact with erosional and depositional processes to produce advancing coasts
(those growing either due to a deposition and/or relative fall in sea level) or retreating coasts (those
being eroded and/or drowned by a relative rise in sea level)
• Human impacts: some coasts are extensively modified whereas others are more natural
• Ecosystem types: such as mangrove, coral, sand dune, saltmarsh and rocky shores add variety to
coastlines.

3. Coastal Zones
The coastal zone includes all
areas from the deep ocean (up to
320km offshore) to 60km inland.
At the coast there is the upper
beach or backshore (backed by
cliffs or sand dunes), the
foreshore (periodically exposed by
the tides) and the offshore area
(covered by water)
The coastal zone is a dynamic
area with inputs and processes
from land, sea and atmosphere.

4. Wave, marine and sub-aerial
processes
Waves are a medium through which energy is transferred.
They are created by the wind blowing across the surface of
the sea. Frictional drag increases as the wind speed
increases, making the wave bigger.
Wave energy depends upon three things:
The strength of the wind.
The length of time the wind has blown for.
The fetch of the wind (the distance it blows over).

5. The wave orbit
The wave orbit is the shape of the wave: varying between
circular and elliptical.
The orbit diameter decreases with depth to a depth roughly
equal to wavelength, at which point there is no further
movement related to wind energy – this point is called the wave
base.

7. Wave definitions
Wave fetch: The distance of open water over which a wave has
passed. Wave crest: Highest point of a wave.
Wave trough: Lowest point of a wave.
Wave height: Distance between trough and crest.
Wave length: Distance between one crest/trough and the next.
Swash: Water movement up a beach.
Backwash: Water movement down a beach.

9. Why waves break…
When out in open water there is little horizontal movement of ocean water, the bulk of the motion is
up and down or vertical. However, this changes slightly when waves approach the coastline. As the
water approaches the coastline it encounters increasing contact with the shelving sea bed, which
exerts a frictional force on the base of the wave. This changes the normal circular orbit of the wave
into an elliptical orbit. As the waves gets closer and closer to the coast the impact of friction grows,
with the top of the wave moving faster than the base of the wave. Eventually a critical point is
reached where the top of the wave (the CREST) curves over and creates a breaking wave. This
breaking wave can be further disrupted by water returning down the coastline back out to sea.

10. Type of breakers
1. Spilling breakers: are associated with gentle beach gradients and steep waves (wave
height relative to wave length) They are characterized by a gradual peaking of the wave
until the crest becomes unstable; resulting in a gentle spilling forward of the crest.
2. Plunging breakers: tend to occur on steeper beaches, with waves of intermediate
steepness. They are distinguished by the shore-ward face of the wave becoming
vertical, curling over, and plunging forward and downward as an intact mass of water.
3. Surging breakers: are found on steep beaches with low steepness waves. In surging
breakers the front face and crest of the wave remain relatively smooth and the wave
slides directly up the beach without breaking.
• Once the breaker has collapsed, the wave energy is transmitted onshore as a ‘wave of
translation’. The swash will surge up the beach, with its speed gradually lessened by
friction and the uphill gradient. Gravity will draw the water back as the backwash gradient.

11. Breaker waves

12. Waves of translation
1. Constructive waves:
• Constructive waves have a short amplitude and a long wavelength.
• They have a low frequency of around 6-8 waves per minute, particularly when these
waves advance over a gently shelving sea floor (formed of fine material: sand). These
waves have been generated far offshore creating a gradual increase in friction and thus a
gradual steepening of the wave front. This creates a spilling breaker, where water
movement is elliptical. As this breaker collapses, the swash surges up the gentle gradient
with maximum energy.
• Constructive waves produce a strong swash,
but a weak backwash, which produces a
gentle beach as material is deposited
but not removed from the beach.
• The supply of new material and the
constant action of pushing the material
up the beach eventually produces berms.

13. Waves of translation
2. Destructive waves:
• Destructive waves are the result of locally generated winds
• They have a high amplitude and a short wavelength.
• They also have a high frequency of 10-14 waves per minute, resulting in a steeply
shelving coastline, where rapid friction and steep circular plunging breakers are
formed.
• The waves have a strong backwash
but a weak swash, so they remove a
lot of material from the beach
producing a steeper beach profile.
The force of destructive waves can
fire material to the back of the

14. Processes and landforms in
coastal areas
Wave Dominated Tide Dominated Wind Dominated
• Shore platforms
• Cliffs
• Beaches
• Spits
• Deltas
• Mudflats
• Sand flats
• Salt marches
• Mangroves
• Deltas
• Sand dunes
High Energy Low Energy High Energy

15. Tides and the tidal cycle
Tides are regular movements in the sea’s surface – the rise and fall of sea levels,
caused by the gravitational pull of the moon and sun on the oceans. Out of the two, the
moon accounts for the larger share of the pull.
When the earth, moon and sun are aligned the gravitational pull is at its greatest. This
creates a Spring tide. A Spring tide results in a high, high tide and low, low tide. This
creates a high tidal range (difference between the highest and lowest tide).
Low spring tides occur just after a new moon whereas high spring tides occur after a
full moon - when the Sun and moon are aligned.
When the sun and moon are at a right angle to the earth we experience Neap tides.
The gravitational pull of the sun partially cancels the moon’s. This results in a low, high
tide and a high, low tide. This creates a low tidal range and results in weaker tidal
currents than normal.

16. Types of tides

17. What influences tides?
1. Tides are influenced by the size and shape of ocean basins.
2. The characteristics of the Shoreline
3. Cariolis forces
4. And Meteorological conditions.
In General:
Tides are greatest in bays and along funnel-shaped coastlines.
In the Northern Hemisphere water is deflected to the right of its path.
During low pressure systems water levels are raised 10 cm for every decrease of 10mb.

18. Tides and the tidal cycle
The difference between high tide and low tide is called the tidal range.
Tidal range varies with distance from the amphidromic point (place where
there is no tidal range) & according to the shape of the coast; the strength of
tidal currents varies enormously.
If the coast is funneled, a tidal bore can be created due to tide advances
being concentrated in a narrow space.
Coastal areas can be classified into…
Micro-tidal: (very low tidal range – less than 2m)
Meso-tidal: (2-4m)
Macro: (over 4m)

19. Tidal range’s influence on
coastal processes:
It controls the vertical range of erosion and
deposition
Weathering + biological activity is affected by the
time between tides
Velocity is influenced by the tidal range and has an
important scouring effect.

20. Rip Currents
Rip currents are strong offshore flows, and often occur when
breaking waves push water up the beach face. This piled-up
water must escape back out to the sea as water seeks its own
level. Typically the return flow (backwash) is relatively uniform
along the beach, so rip currents aren't present. However, If there
is an area where the water can flow back out the ocean more
easily, such as a break in the sand bar, then a rip current can
form. When water from the highest sections of breakers travels
upshore upon returning as backwash it moves through the points
where lower sections have broken, creating a strong backwash
current. Once rip currents are formed they modify the beach by
creating cusps which perpetrate the currents.

21. Rip currents

22. Discordant Coasts
On a discordant coastline, alternating layers of hard
and soft rock are perpendicular to the coast.
Because the soft rock is exposed, it is eroded faster
than the hard rock. This differential erosion creates
headlands and bays along discordant coastlines.

23. Concordant Coasts
Concordant coasts have alternating layers of hard
and soft rock that run parallel to the coast. The hard
rock acts as a protective barrier to the softer rock
behind it preventing erosion. If the hard rock is
breached though, the softer rock is exposed and a
cove can form (e.g., Lulworth Cove).

24. Storm Surges
Storm surges are changes in the sea level, caused
by intense low pressure systems and high wind
speeds. For every drop in pressure of 10mb, sea
water is raised by 10cm. Therefore during tropical
cyclones, pressure may drop by 100mb resulting in a
sea level rise of 1m! Storm surges can bring
catastrophic consequences and are intensified on
funnel shaped coastlines.

25. Storm Surge

26. Wave refraction
It is very rare for waves to approach a regular uniform coastline, as most
have a variety of bays, beaches and headlands. Because of these
features, the depth of water around a coast varies and as a wave
approaches a coast its progress is modified due to friction from the
seabed, halting the motion of waves.
As waves approach a coast, due to the uneven coastline, they are
refracted so that their energy is concentrated around headlands but
reduced around bays. Waves then tend to approach coastline parallel to it,
and their energy decreases as water depth decreases.
However, due to the complexities of coastline shapes, refraction is not
always fully achieved resulting in long shore drift (which is a major force for
transporting material along the coast).

28. Coastal erosion processes
1. Hydraulic action: As waves break
against the face of cliffs, any air trapped
in cracks, joints and bedding planes is
momentarily placed under great
pressure. As the wave retreats this
pressure is released with explosive
force. This stresses the coherence of
the rock, weakening it and aiding
erosion. This is particularly obvious in
well bedded rocks such as limestone,
sandstone, granite and chalk, as well as
poorly consolidated rocks such as clays
and glacial deposits. It is most notable
during times of storm wave activity.

29. Coastal erosion processes
2.Abrasion/Corrasion: This is the process
whereby a breaking wave hurls pebbles and
shingle against the coast breaking bits off
and smoothing surfaces.
3. Attrition: Takes place as other forms of
erosion continue. Rocks and pebbles
constantly collide with one another as they
are moved by waves action, resulting in
reduced size of beach material and
increased roundness as the impact of 2
hitting smooth's away rough edges.

30. Coastal erosion processes
Solution: Is a form of chemical erosion whereby rocks
containing carbonates such as limestone and chalk are
dissolved by weak acids in the water – supplied by
organisms such as barnacles and limpets.
Calcium carbonate + weak acids = Calcium bicarbonate
(soluble).

31. Sub-aerial processes
Salt crystallization: The process whereby sodium and magnesium compounds
expand in joints and cracks by 300% when temperatures fluctuate between 26-28
degrees thereby weakening rock structures.
Freeze thaw= water becomes trapped in cracks in rocks, freezes when temperatures
drop below 0 degrees and therefore expand by 10%. As they expand they put extra
pressure onto the rock, until the ice melts when temperatures rise. After many
repeated cycles the rock fragments and weakens.
Biological weathering: where living organisms – such as mollusks, sponges and sea
urchins on low energy coasts physically break up structures.
Solution weathering: the chemical weathering of calcium carbonate by acidic water,
which tends to occur in rock pools due to the presence of organisms secreting
organic acids.

32. Sub-aerial processes cont.
Mass Movement: Mass movement can be defined as the large scale movement of weathered material in response to gravity.
Essentially, it’s when a cliff or other structure that is not horizontally orientated has been weathered to the point at which it starts
to collapse.
Rock falls: Freeze thaw weathering on a cliff breaks the rocks up into smaller pieces which can then free fall. This occurs
commonly on cliffs with lots of joints as the joints make it easier to break up the rock. If the cliff is undercut by the sea, it can
loose some of its stability, increasing the likelihood that a rock fall will occur.
Soil Creep: Soil creep is an incredibly slow process. It occurs on very gentle slopes and produces an undulated (wavy) surface.
Damp soil moves very slowly down hill due to the increase in its mass (since it’s wet).
Landslides : After being soaked by water, cliffs made from soft rock will begin to slip due to the rock being lubricated.
(Rotational) Slumping: Slumping happens for similar reasons to landslides. Heavy rainfall makes the rock heavier due to it
absorbing the water and the water also acts as a lubricant. The difference with slumping is that it happens on a concave
surface, which causes the cliff to form a crescent shape.
Mudflow: Mudflow is a very dangerous form of mass movement which occurs on steep slopes with saturated soil and little
vegetation. The lack of vegetation means that there is nothing to bind the soil together, promoting mass wasting. The saturated
soil becomes heavier and is lubricated, leading to the rapid movement of a lot of mud downhill.

33. Wave transportation:
1. Traction: Grains slide or roll along the sea floor – a low form of transport. In weaker
currents sands may be transported, whereas in stronger currents pebbles and
boulders may be transported.
2. Saltation: Is when grains hop along the seabed in a skipping motion. Moderate
currents may transport sand, whereas strong currents may transport pebbles and
gravel.
3. Suspension: Suspension is when grains are carried by turbulent flow and are held
up in the water. Suspension occurs when moderate currents are transporting silts or
strong currents transporting sands. Grains transported as wash loads are
permanently in suspension and typically consist of clays and dissolved materials.
4. Solution: Solution is when particles, invisible to the naked eye are carried in the
waters current.

34. Longshore drift
Longshore drift is a process responsible
for moving significant amounts of sediment
along the coast. This usually occurs in
one direction as dictated by the prevailing
wind. For example the prevailing wind
along the Holderness Coast is north-
easterly. As the result waves break on to
the beach obliquely at an angle of around
45 degrees. The swash moves beach
material along the beach and the
backwash, under gravity, pulls the material
back down the beach at right angles to the
coastline. Over time this creates a net shift
of material along the coast.

35. Sediment cells
`The coastal sediment
system’ or `littoral cell system’
is a simplified model that
examines coastal processes
and patterns in a given area.
Each sediment cell is a self-
contained cell in which inputs
and outputs are balanced.
There are 11 such cells
around the UK.

36. Dynamic equilibrium
The concept of dynamic equilibrium is important to
Littoral cells. The concept states any system is as a
result of inputs and processes operating within it.
Changes to an input i.e.. Sediment increase, has a
knock on effect on processes such as Longshore
drift, and a resulting change in landforms will occur.
The balance changes in sync.

37. Coastal landforms

38. Wave cut platform
The sea cliff is the main landform along coasts where marine erosion is
dominant. The basic formation of a sea cliff is the same everywhere.
Waves attack the base of the newly exposed rock faces. By hydraulic
action and abrasion, and the other processes of coast erosion, the
base of the cliff is undercut to form a wave-cut notch. The rock face
above the effects of wave action begins to overhang. As waves
continue their relentless attack upon the base of the cliff, the size of the
overhang increases until the weight of the rock above can no longer be
supported and a section of the cliff collapses. Active marine erosion
begins again at the base of the cliff after the waves have removed the
loose rock, leading to further collapses and gradual retreat inland of the
position of the cliff. Therefore every cliff coastline is a sign that land is
being lost. As a consequence of cliff retreat another landform. The
wave-cut platform, is formed.

40. Headlands and Bays
Headlands and bays, such as Swanage Bay, form on discordant coastlines,
where hard and soft rock run in layers at 90˚ to the water. Alternating layers of
hard and soft rock allow the sea to erode the soft rock faster, forming a bay but
leaving hard rock sticking out, known as a headland. The altering rate of erosion
of hard and soft rock is known as differential erosion. As the bay develops, wave
refraction around the headlands begins to occur, increasing erosion of the
headlands but reducing the erosion and development of the bay due to a loss of
wave energy. Headlands and bays can form on concordant coastlines too, as
has happened with Lulworth Cove, but this requires the rock to have already
been weakened, possibly during an ice age. Irrespective of whether the coastline
is concordant or discordant, as wave refraction takes place around the
headlands and erosion of the bay is reduced, sub-aerial weathering such as
corrosion and corrasion begins to weather the bay, furthering its development.

42. Cliffs
A cliff is a vertical, near vertical or sloping wall of rock or sediment that
borders the sea. They generally differ in their angle of slope because
of their rock structure and geology, but the processes involved in their
formation are the same.
They result from the interaction of a
number of processes:
Geological.
Sub-aerial.
Marine.
Meteorological.
Human activity.

43. Cliffs
Rocks tend to form in layers of different rock types known as beds. These beds
are subjected to tectonic forces that tilt and deform them so they dip at an
angle. The angle the beds dip at affects how they are eroded and the profile of
the resulting cliffs. As well as this rock structure plays an important role in
variation between cliff profiles:
Vertical dipping beds, produce steep cliffs
Beds that dip seaward produce gentler cliffs but are less stable because
loose material can slide down the bedding planes by mass movements.
Landward dipping beds produce stable and steeper cliffs.

44. Cliffs
Where dip or foliation lies to seaward then
the cliff face is inherently unstable.
Removal or collapse of rock towards the
cliff base leads to rock slides/land slides
(depends on material)

45. Cliffs
Where rocks dip inland,
steep, but sub-vertical
and relatively stable
cliffs form.

46. Cliffs continued
Many cliffs are composed of more than one rock type - these
are known as COMPOSITE CLIFFS. The exact shape and
form of the cliff will depend on such factors as strength and
structure of rock, relative hardness and nature of waves
involved:
• Cliffs that are composed of strong, hard rocks such as
granite will be eroded slowly with little cliff retreat.
• Whereas, cliffs composed of weaker rock strength
experience cliff retreat more rapidly.

47. Cliffs continued.
Depending on the relative position of the weaker rock in
composite cliffs determines the different landforms that are
created. For example:
• If less resistant, weak rock is at the base of the cliff,
undercutting and collapse may occur.
• If the less resistant rock is near the top of the cliff, it may be
subjected to sub-aerial processes.

48. Cliffs cont.
Cliff morphology also is influenced by the permeability of a
rock. For example:
• Cliffs which have impermeable rock overlying permeable
rocks limit percolation and therefore are more stable,
preventing mass movement.
• Whereas, cliffs in which permeable rock overlies
impermeable rock, water may soak into the cliff, making
slope failure more likely as water builds up between the
junction of the two rocks.

49. Cliffs continued
Cliff form can also be related to latitude. In the tropics, low
wave energy levels and high rates of chemical weathering
produce low gradient casts.
Coastal cliffs in high latitudes are also characterized by
relatively low gradients since the per glacial processes
produce large amounts of cliff base materials.
Temperate regions tend to have the steepest cliffs. The
rapid removal of debris by high energy waves prevents
the build up of material at the base,.

50. Beaches
The term beach refers to the accumulation of material deposited between
high and low tidal limits, which shelves downwards towards the sea. A
typical beach has three zones
1. Backshore
2. Foreshore
3. Offshore
A whole variety of materials can be moved along the coast by waves, fed
by longshore drift. The coarse material is found deposited in the
backshore and foreshore zones as littoral deposits. The finer material,
worn down largely by attrition is usually found in the offshore zone as
neritic deposits.

52. The Backshore:
The backshore is a cliff or is marked by a line of sand dunes.
Above and at HWM (high water mark) there may be a shingle/storm ridge. This is an
area of coarse material pushed up the beach by spring tides, aided by storm waves
which fling material well above the level of normal tidal waves. This coarse material
then usually cannot be reached and remains largely untouched.
There are often a series of smaller ridges formed beneath the storm ridge known as
berms. These are build ups of finer material that mark the successive high tides that
follow the spring tide through to the neap tide.
The seaward edge of the berm is often scalloped and irregular due to the creation of
beach cusps. Cusps are semi-circular depressions; they are smaller and more
temporary features formed by a collection of waves reaching the same point. The sides
of the cusp channel the incoming swash into the centre of the depression and this
produces a stronger backwash which drags material down the beach from the Centre of
the cusp. The spacing of cusps is related to wave height and swash strength.

53. Depositional landforms:
Backshore/Foreshore

54. The foreshore:
The foreshore is exposed at low tide.
Ridges and runnels form parallel to the shore line in the
foreshore zone. Ridges are areas of the foreshore that
are raised above the adjacent shore which dips into
a Runnel. Ridge and runnel systems are formed due to
the interaction of tides, currents, sediments and the beach
topography. They only form on beaches with a shallow
gradient. They form as a simple drainage route for tides.
Water flows in and out via the runnel.

55. The offshore
Offshore, the first material is
deposited. In this zone, the
waves touch the seabed
and so the material is
usually disturbed,
sometimes being pushed
up as offshore bars, when
the offshore gradient is very
shallow.

56. Factors affecting beach form
Beach form is affected by the size, shape and composition of materials, the tidal range and wave characteristics.
As storm waves are more frequent in winter and swell waves more important in summer, many beaches differ in
their winter and summer profile. Thus the same beach may produce two very different profiles at different times of
the year. For example, constructive waves in summer may build up the beach but destructive waves in winter may
change the size and shape of the beach.
The relationship between wave steepness and beach angle is a two way affair. Steep destructive waves reduce
beach angle whereas gentle constructive waves increase it. In turn, a low gradient produces shallow water which in
turn increases wave steepness. Hence plunging waves are associated with gentle beaches whereas surging waves
are associated with steeper beaches.
Sediment size affects the beach profile through its percolation rate. Shingle/pebbles allow rapid infiltration and
percolation, so the impact of swash and backwash are reduced. As the backwash is reduced it will not impeded the
next swash. If the swash is stronger than the backwash then deposition may occur. By contrast, sand produces a
lower angle and allows less percolation. Backwash is likely to be greater than on a gravel beach.
The pattern is made more complex because sediment size varies up a beach. The largest particles, the products of
cliff recession, are found at the rear of a beach. Large, rounded material on the upper beach is probably supplied
only during the highest spring times and is unaffected by ‘average’ conditions. On the lower beach wave action is
more frequent, attrition is common and consequently particle size is smaller.

57. Depositional processes and
features
There are two types of coastlines
1. Swash Aligned Coasts: are produced where the waves break in
line (parallel) with the coast. Swash and backwash movements
move material up and down the beach producing many coastal
features. Swash aligned beaches are smoothly curved, concave
beaches.
2. Drift aligned coasts: beaches are produced where waves break at
an angle to the coast. The swash therefore occurs at an angle but
the backwash runs perpendicular to the beach. As a result,
material is transported along the beach via longshore drift.

58. Drift aligned beaches transfer sediment along the beach due to the angle of wave approaching the shoreline
on an angle, under the influence of prevailing winds. As a consequence, large wide beaches struggle to
establish. However, these beaches are associated with a range of depositional features that develop along
the coast, including spits. Prevailing wind brings waves in on an angle which is slightly reduced in the
nearshore by wave refraction. As waves break, their swash transports sediment up the beach at angle but
the backwash under the influence of gravity bring it back perpendicular. As a result sediment is transported
down the beach in a zigzag pattern. Most sediment is suspended in the water but when moved by the
breaking wave it is transported through saltation and traction. A strong current is also present in the
nearshore, called the longshore current. Sediment is also transported in the longshore current. The current
varies in strength from beach to beach but works like stream down within trough between the beach and an
offshore bar. It is these offshore currents that explain the all-too-common experience, when bathing at the
seaside, you enter the sea at one point but when you come out you realize that you have drifted some
distance down the beach. Many a time as a child this caused me great stressAt breaks within the offshore
bar, surfers will be all-too-familiar with the powerful rip-currents that develop
Drift Aligned Beaches

59. LOCALISED DEPOSITIONAL FEATURES
Bars, spits and other localised features develop where:
1. Abundant material is available, particularly shingle and sand.
2. The coastline is irregular due to for e.g. geological variety.
3. Deposition is increased by the presence of vegetation
4. There are estuaries and major rivers.

60. Spit Formation
A spit is a stretch of sand or shingle extending from the mainland out to sea. They develop where
there is a sudden change in the shape of the coastline such as at a headland. Normally, longshore
drift transports beach sediment along a coastline. When the shape of the coastline changes
substantially however, longshore drift continues to transport material in the same direction rather
than following the coastline. This transports the material out to sea. As the strength of the drift
weakens away from the coastline, the sediment is deposited. Deposition can be brought about
earlier near estuaries. The flow of water into the sea at an estuary is stronger than the drift, forcing
the sediment to be deposited.
The deposition of sediment forms a spit but its shape changes as a result of wave refraction.
Refraction around the end of a spit curves it into a “hook” forming a recurved spit. As the area
behind a spit is sheltered from waves and the wind, it provides the perfect environment for salt
marshes to develop.
Spits are eroded by the sea and wind but a constant supply of sediment from longshore drift
ensures their continued existence. Events such as storms change the shape of a spit drastically
over short periods of time though. During a storm event, erosion exceeds deposition so a lot of
material is removed from the spit, changing its shape

62. Bar formation
A bar is a ridge of material that
is connected at both ends to the
mainland. It is located above
sea-level. If a spit continues to
grow lengthwise, it may
ultimately link two headlands to
form a bay bar. These are
composed either of shingle, as
in the case of the Low Bar in
Cornwall, or of sand, such as
the nebrung of the Baltic coast.

63. Barrier Islands
Barrier islands are natural sandy breakwaters that form parallel to a flat coastline. By far the world’s
longest series is that of roughly 300 islands along the East and Southern coasts of the USA. The
islands are generally 200-400 m wide, but some are wider. Barrier islands form only under certain
conditions and America's eastern seaboard provides the ideal conditions for barrier islands…
1. Over the last 15000 years, the sea level has risen by 120m as glaciers and ice caps have melted.
2. Wind and waves have formed sand dunes and beach ridges at the edge of the continental shelf.
3. As the sea levels rose, the water broke through the ridges and dunes, flooding the low area behind
it forming a lagoon.
4. This resulted in the former dune area becoming an island.
5. Constant action by waves and continuing rise in sea levels caused islands to migrate landward as
sand was removed from the beach and deposited inland.

64. Tombolo
If a ridge of material
links an island with
the mainland, this
ridge is called a
tombolo. An
example of this is
Chesil Beach on the
south coast of
England.

65. Cuspate Forelands
Cuspate forelands consist
of shingle ridges
deposited in a triangular
shape, and are the result
of two separate spits
joining, or the combined
effects of two distinct sets
of regular storm waves.

66. Sand dunes
Sand dunes form where there is a reliable supply of sand, strong onshore winds, a large tidal range and vegetation to
trap the sand.
Extensive sandy beaches are almost always backed by sand dunes because strong onshore winds can easily
transport inland the sand that has dried out and is exposed at low water. The sand grains are trapped and deposited
against any obstacle on land, to form dunes.
Vegetation causes the wind velocity to drop, especially in the lowest few cm above the ground, and the reduction in
velocity reduces energy and increases the deposition of sand.
Dunes can be blown inland and can therefore threaten coastal farmland and even villages.
Special methods are used to slow down the migration of dunes…
1. Planting of special grasses, such as marram which has a long and complex tap root system that binds the soil
2. Erecting brushwood fences to reduce sand movement
3. Planting of conifers which can stand the saline environment

67. Sand dunes continued
There are several conditions that need to be met for sand dunes to develop. First, a large supply of
sediment is needed. The best place to get this is from a large tidal flat. An area with a large tidal range
(a big difference between the high and low tide) will result in a lot of sand being exposed to the wind,
ready to be transported. This brings us to our next condition. A (relatively) strong and continuous wind
is needed to move sand grains and transport them inland via saltation. The best place to find strong
winds that don’t change direction is in areas that face the prevailing wind direction.
With these conditions met, it’s now only a matter of time until a sand dune starts to form. Obstacles
such as rocks or human rubbish are deposited at the strandline—essentially the high water mark.
These objects block the wind causing sand grains that are being transported to be deposited. Over
time, the sand grains will build up and encompass the object forming a very small embryo dune.
Eventually pioneer species of plants will start to grow on the embryo dune. As they do so, they bind
the sand together, increasing the stability of the dune. The vegetation itself also traps sand causing
the embryo dune to grow even more. As the dune grows it becomes a foredune and a new embryo
dune begins to develop in front of it. This is the beginning of a sand dune succession.

68. Sand dune succession

69. Sand dune succession
Sand is moved by the wind. However, wind speed varies with height above the surface. As most grains protrude above this height
they are moved by saltation. The strength of the wind and the nature of the surface are important. Irregularities cause increased wind
speed and eddying resulting in more material being moved. On the leeward side of irregularities, wind speed is lower, transport
decreases and deposition increases.
For dunes to become stable, vegetation is required. Plant succession can be interpreted by the fact that the oldest dunes are furthest
from the sea and the youngest closer to shore. On shore conditions are windy, arid and salty. The soil contains few nutrients and
mostly sand – hence the fore dunes being referred to as YELLOW DUNES. Few plants can survive, although sea couch and marram
can tolerate these conditions.
Once the vegetation is established it reduces wind speed close to the ground level. The belt of no wind may increase to a height of
10mm. As grasses such as sea couch and marram need to be buried by fresh sand in order to grow, they keep pace with deposition.
As the marram grows it traps more sand. As it is covered it groves more and so on.
Once established the dunes should continue to grow as long as there is a supply of sand. However, once another younger dune, a
fore dune, becomes established the supply of sand is reduced. As the dune gets higher the supply of fresh sand is reduced to dunes
further back. Thus marram dies out. In addition as wind speeds are reduced, evapotranspiration losses are less and the soil is
moister. The decaying marram adds some nutrients to the soil, which in turn becomes more acidic. In the slacks, the low points
between the dunes, conditions are noticeably moister and marsh vegetation may occur.
Towards the rear of the dune system ‘grey dunes’ are formed (grey due to the presence of humus in the soil). The climax vegetation
found here depend largely upon the nature of the sand. If there is a high proportion of shells (providing calcium) grasslands are
found. By contrast, acid dunes are found on old dunes where the calcium has been leached out, Here acid loving plants such as
heather dominate. Vegetation at the rear of sand dune complex is quite variable/.

70. Definitions
• Embryo dune: The first part of the dune to develop. Stabilisation occurs via marram and Lyme grass,
which act as traps for sand. Conditions are dry and plants adapt to this via long roots, or thorny leaves to
reduce evapotranspiration.
• Yellow dune: Colour is due to a lack of humus, but with distance inland they become increasingly grey
due to greater amounts of humus. Heights can reach 5m and plants include sand sedge, sea holly, and
red fescue.
• Fixed grey dunes: Limited growth due to distance from beach. Far more stable as shown by existence of
thistle, evening primrose, bracken, bramble and heather.
• Dune slacks: Depressions between dune ridges, which will be damp in summer and water-filled in winter.
Species include water mint, rushes, and weeping-willow.
• Blow outs: Often evidence of over use by humans. Large 'holes' that appear in the dunes

71. Mudflats and Saltmarshes
The intertidal zone – the zone between high tide and low tide –
experiences severe environmental changes in salinity, tidal inundation
and sediment composition. Halophytic (salt-tolerant_ plants have
adapted to the unstable, rapidly changing conditions.
Salt marshes are typically found in three locations:
1. Low energy coastlines
2. Behind spits and barrier islands
3. In estuaries and harbor's
• Salt accumulates in these situation's and on reaching sea level forms
mud banks. With the appearance of vegetation, saltmarshes is formed.
The mud banks are often intersected by creeks.

72. Salt marsh formation
1. Salt marshes only form in low energy environments where there is shelter from the wind and waves. Depositional
landforms such as spits can help provide this shelter. Salt marshes require a large input of sediment which can
arrive from the sea and rivers. The most likely place along a coastline where you’ll find this sort of sediment input is
near a tidal flat. The low gradient of a tidal flat means that any rivers that flow into it will very quickly deposit any
sediment they’re transporting. At the same time, the periodic flooding of the tidal flat by the tides will deposit even
more sediment.
2. Over time, sediment accumulates and the elevation of the tidal flat increases in a process known as coastal
accretion. This reduces the duration of tidal flooding allowing a small selection of plants to grow on the now
developing salt marsh. These plants are halophytic—they love salt—and are capable of surviving underwater for
several hours a day. They’re often called pioneer species because of their hardy nature and, well, pioneering growth
on salt marshes. These plants, which include species of cord grass (Spartina) and glasswort (Salicornia)1, have
several adaptations that not only help them thrive in saline environments but also help aid coastal accretion.
3. Long blades of cord grass trap sediment that is too fine to settle out of water in a salt marsh, building up a muddy
substrate. At the same time, the roots of the cord grass plant (that are long to tap into the water table) help stabilize
already deposited sediment, aiding coastal accretion. Pioneer species such as Spartina alterniflora (a species of
cord grass) are invasive plants that spread rapidly. Once these plants are introduced to a salt marsh, coastal
accretion takes place quickly and the elevation of the salt marsh increases greatly. This creates new environments
that are submerged by the tide for shorter periods of time, allowing even more species of plants and animals to
colonise the salt marsh.

73. Factors affecting salt marshes

74. Coral Reefs

75. Coral reefs
Coral reefs are calcium carbonate structures, made up of reef-building stony
corals. Coral is limited to the depth of light penetration and so reefs occur in
shallow water, ranging to depths of 60m. This dependence on light also means
that reefs are only found where the surrounding water contain relatively small
amounts of suspended material. Although corals are found quite widely, reef-
building corals live only in tropical seas, where temperature, salinity and a lack
of turbid water are conducive to their existence.
Coral reefs occupy less than 0.25% of the marine environment, yet they shelter
more than 25% of all known marine life, including polyps, fish, mammals, turtles,
crustaceans and molluscs. There are as many as 800 different types of rock-
forming corals. Some estimates put the total diversity of life found in, on and
around all coral reefs at up to 2 million species.

76. The Development of Coral
All tropical reefs begin life as polyps – tiny, soft animals, like sea
anemones – which attach themselves to a hard surface in shallow seas
where there is sufficient light for growth.
As they grow many of these polyps exude calcium carbonate, which forms
their skeleton
As they grow and die these rock-forming corals create the reefs.
Polyps have small algae – zooxanthellae, growing inside them. There is a
symbiotic relationship between the polyps and the algae (they both benefit
from the relationship). The algae get shelter and food from the polyp, while
the polyp also get some food via photosynthesis. This photosynthesis
means that algae need sunlight to live, so corals only grow where the sea
is shallow and clear.

78. Rate of growth in Coral reefs
Tropical reefs grow at rates ranging from less than
2.5cm – 60cm per year, forming huge structures over
incredibly long periods of time – which makes them
the largest and oldest living systems on earth.
The 2600Km Great Barrier Reef off Eastern Australia
was formed over 5 million years!!

79. Factors that influence the
distribution of coral reefs1. Temperature: no reefs develop where the mean annual temperature is below 20°c. Optimal conditions for growth are
between 23°-25°C
2. Depth of water: most reefs grow in depths of water less than 25m, so are generally found on the margins of continents and
islands.
3. Light: corals prefer shallow water because the tiny photosynthetic algae that live in the coral need light – in return they
supply the coral polyps with as much as 98% of their food requirements.
4. Salinity: corals are marine organisms and are intolerant of water with salinity levels below 32 psu although they can tolerate
high salinity levels (42 psu +) as found in the Red Sea or Persian Gulf.
5. Sediment: sediment has a negative effect on coral – it clogs up their feeding structures and cleansing systems and
sediment-rich water reduces the light available for photosynthesis.
6. Wave action: coral reefs generally prefer strong wave action which ensures oxygenated water and where there is a stronger
cleansing action. This helps remove any trapped sediment and also supplies microscopic plankton to the coral. However, in
storm conditions, the waves may be too destructive for the coral to survive.
7. Exposure to air: coral die if exposed to air for too long – therefore they are mostly found below the low tide mark.

81. Types of reefs

82. Types of Coral Reefs:
Fringing Reef
Fringing Reefs are those that fringe
the coast of a landmass. They are
usually characterised by an outer
reef edge capped by an algal ridge, a
broad reef flat and a sand floored
‘boat channel’ close to the shore.
Many fringing reefs grow along
shores that are protected by barrier
reefs and are thus characterised by
organisms which are best adapted to
low wave energy conditions.

83. Barrier Reefs
Barrier reefs occur at greater distances
from the shore than fringing reefs and are
commonly separated from it by a wide and
deep lagoon. Barrier reefs tend to be
broader, older and more continuous than
fringing reefs. Barrier reefs forms as the
oceanic island begins to sink into Earth's
crust due to the absence of volcanic island
building forces, the added weight of the
coral reef, and erosion at the surface of the
island. As the island sinks, the coral reef
continues to grow upward.

84. Atoll Reefs
Atoll reefs rise from submerged volcanic
foundations and often support small
islands of wave-borne detritus. Atoll reefs
are essentially indistinguishable in form
and species composition from barrier
reefs except that they are confined to the
flanks of submerged oceanic islands,
whereas barrier reefs may also flank
continents. There are over 300 atolls in
the Indian and Pacific oceans but only 10
found in the western Atlantic.

85. Patch Reef
Describes small
circular or irregular
reefs that rise from the
sea floor of lagoons
behind barrier reefs or
within atolls.

87. Origin: Charles Darwin theory
The origin of fringing reefs is quite clear – they simply grow seaward from the land. Barrier reefs and atolls,
however, seem to rise from considerable depth, far below the level at which coral can grow, and many atolls
are isolated in deep water. The lagoons between the barrier and the coast are usually 45-100m in depth,
and often many kilometres in width – and this requites some explanation.
In 1842 Charles Darwin, explained the growth of barrier reefs and atolls as a gradual process, the main
reason being subsidence (gradual sinking of land). In his book, Darwin outlined the ways in which coral
reefs could grow upwards from submerging foundations. From this, it became clear that fringing reefs might
be succeeded by barrier reefs and then by atoll reefs.
A fringing reef grows around an island and as the island slowly subsides, the coral continues to grow,
keeping pace with the subsidence. Coral growth is more vigorous on the outer side of the reef, so it forms a
higher rim, whereas the inner part forms an increasingly wide and deep lagoon. Eventually the inner island
is submerged, forming a ring of coral that is the atoll.
Supporters of Darwin have shown that submergence has taken place, as in the case of drowned valleys
along parts of Indonesia. However, in other areas, such as the Caribbean, there is little evidence of
submergence.

88. Origin cont: Sir John
Murrays theory
An alternative theory was that of Sir John Murray, who in
1872 suggested that the base of the reef consisted of a
submarine hill or plateau rising from the ocean floor.
These reached within 60m of the sea surface and
consisted of either sub-surface volcanic peaks or wave-
worn stumps.
According to Murray, as a fringing reef grows, pounded by
breaking waves, masses of coral fragments gradually
accumulate on the seaward side, washed there by waves
and are cemented into a solid bank.

89. Origin: Daly’s theory
Another theory was that of Daly. He suggested that a rise in
sea level might be responsible.
A rise did take place in post glacial times as ice sheets melted.
He discovered traces of glaciation on the sides of Mauna Kea
in Hawaii. The water there must have been much colder and
lower (about 100m) during glacial times. All coral would have
died, and any coral surfaces would have been eroded by the
sea. Once conditions started to warm, and sea level was
rising, the previous coral reefs provided a base for the upward
growth of coral. This theory helps account for the narrow,
steep sided reefs that comprise most atolls, so of which have
75° slopes.

90. Which theory?!
Darwin’s theory still receives considerable support.
While Daly was correct in principle, it is now believed
that erosion of the old reefs was much less rapid
than previously believed, and that the time available
during the glacial low sea-level stages was
inadequate for the formation of these bevelled
platforms. Much of the erosional modification is now
believed to be due to sub-aerial karstic (limestone)
processes such as carbonation solution.

91. The value of coral : $$$
Coral reefs are among that most biologically rich ecosystems on Earth. Coral reefs resemble tropical rainforests in two ways: both thrive under
nutrient-poor conditions (where nutrients are largely tied up in living matter), yet support rich communities through incredibly efficient recycling
processes. Additionally, both exhibit very high levels of species diversity. However, corral reefs and other marine ecosystems contain a greater
variety of life forms than do land inhabitants.
Coral reefs are not only important for their biodiversity, they are important to people too:
1. Seafood: in LEDCs, coral reefs contribute about ¼ of the total fish catch, providing food for up to a billion people in Asia alone. If properly
managed, reefs can yield on average, 15 tonnes of fish and other seafood per km squared / year.
2. New medicines: Coral reefs offer particular hope because of the array of chemicals produced by many of these organisms for self
protection. Corals are already being used for bone grafts, and chemicals found within several species appear useful for treating viruses,
leukaemia, skin cancer and other tumours.
3. Other products: reef ecosystems yield a host of other economic goods, ranging form corals and shells made into jewellery and tourism
curios to live fish and corals used in aquariums, and sand and limestone used by the construction industry.
4. Recreational value: The tourism industry is one of the fastest growing sectors of the global economy. Coral reefs are a major draw for
snorkelers, scuba divers and recreational fishers.
5. Coastal protection: coral reefs buffer adjacent shorelines through wave action and the impact of storms. The benefits of this protection are
widespread and range from maintenance of highly productive mangrove fisheries and wetlands to supporting local economies that are
built around ports and harbours, which in the tropics is often sheltered by nearby reefs.

92. Human impact on Coral

93. Human impact
Overfishing
Destruction of the coastal habitat
Pollution from industry farms and households are endangering not only fish – the leading individual source of animal
protein in the human diet – but also marine biodiversity and even the global climate.
There are natural threats too…
Dust storms from the Sahara have introduced bacteria into Caribbean coral
While global warming may cause coral bleaching.
Many areas of coral in the Indian Ocean were destroyed by the 2004 tsunami.
According the the World Resources Institute, 57% of the world’s coral reefs are at high or medium risk of degradation with
more than 80% of SE Asia’s extensive reef systems under threat.

94. Coral Bleaching
Reef-building corals need warm, clear water. Unfortunately pollution, sedimentation, global climate
change and several other natural and anthropogenic pressures threaten this fundamental biological
need, effectively halting photosynthesis of the zooxanthellae (algae inside polyps) and resulting in
the death of the living part of the coral reef.
Coral lives in a symbiotic relationship with algae called zooxanthellae. This algae lives within the
coral animal tissue and carries out photosynthesis, providing energy not only for themselves but for
the coral too. This algae is what gives coral its colour. However, when environmental conditions
become stressful, zooxanthellae may leave the coral, leaving the coral in an energy deficit and
without colour – a process that is referred to as coral bleaching. If the coral is recolonized by
zooxanthellae within a certain time, the coral may recover, but if not the coral will die.
Coral bleaching can be caused by increases in water temperatures of as little as 1-2°c above the
average annual maxima. The shallower the water the greater the potential for bleaching. As well as
being caused by unusually warm waters – particularly if the water temperature exceeds 29°c –
bleaching may also be the result of changes in salinity, excessive exposure to ultraviolet radiation
and climate chance.

95. Climate change, coral and
people
About 500 million people depend on coral reefs for some food, coastal
protection, building materials and income from tourism. Among these, about
30 million people are dependent on coral reefs to provide their livelihoods,
build up their land and support their cultures.
Global climate change threatens these predominantly poor people, with many
living in 80 small developing countries. Human wellbeing will be reduced for
many people in rapidly growing tropical countries: 50% of the worlds
population are predicted to live on coasts by 2015. This growth is putting
unstainable pressures on coastal resources.
In 2009 the UN environmental programme estimated that coral reef area of
284000 km squared provides the world with more than $100 billion USD per
annum in goods and services. Even moderate climate change will seriously
deplete that value.

96. Evidence of climate change
damage on coral reefs
1. Mass coral bleaching was unknown in the long oral history of many countries such as
the Maldives and Palau, before their reefs were devastated in 1998. About 16% of the
worlds corals bleached and died in 1998. In that year 500-1000 year old corals died in
Vietnam, Indian ocean and Western Pacific.
2. The hottest years recorded in the tropical oceans were in 1997/98- 2005. In this time
major bleaching took place in Caribbean corals. The bottom cover of corals on
Caribbean corals have dropped by more than 80% since 1977.
3. The growth rate of coral species has declined by 14% on the Great Barrier Reef since
1990, either due to temperature stress of ocean acidification or both.
4. Ocean temperature have risen in all oceans in the last 40 years as seen from satellite
images and other measures over 135 years from the National Oceanic.

97. Sustaining Coral
Global climate change seriously threatens the future of coral reefs. Current scientific thought is that coral reefs
may become one of the first ecosystem causalities of climate change and could become functionally extinct if co2
levels rise about 450ppm – which could happen by 2030. Having huge affects on the livelihoods of up to 500
million people. Global temperatures are expected to rise by at least 2° c leading to widespread coral bleaching,
extinction of coral species, more fragile skeletons and greater risk of storm damage, making low lying coastal
communities more vulnerable to coastal hazards.
To avoid permanent damage and support people in the tropics it is recommended that..
1. The world community reduces the emissions of greenhouse gases and develops plans to sequester co2
2. Damaging human activities (sedimentation, overfishing, blasting coral) are limited to allow coral to recover
from climate change threats.
3. Assistance provided to LEDCs
4. Local coastal management practices to be introduced.
Strategies are developed to cope with climate change damage.
5. Management, monitoring and enforcement of regulations improved etc.

98. Sustaining coral reefs
Short clip:

99. Sustainable management of
coasts
Human pressures on coastal environments create
the need for a variety of coastal management
strategies. These may be long-term or short term,
sustainable or non-sustainable. Successful
management strategies require a detailed knowledge
of coastal processes. Rising sea levels, more
frequent storm activity and continuing coastal
developmental are likely to increase the need for
coastal management.

100. Shoreline management
plans (SMPs)
SMPs are plans in England and
Wales designed to develop
sustainable coastal defence
schemes. Sections of the coasts are
divided up into littoral cells and
plans are drawn up for the use and
protection of each zone. Defence
options include…
1. Do nothing
2. Maintain existing levels of
coastal defence
3. Improve the coastal defence
4. Allow retreat of the coast in
selected areas.
Coastal management involves a wide
range of issues…
• Planning
• Coastal protection
• Cliff stabilisation
• Coastal infrastructure including
seawalls, paths etc.
• Control of beaches and public safety
• Beach cleaning
• Pollution and oil spills etc.

101. Coastal defence
Coasts are vulnerable locations that need protecting. They need protecting
because of the economic value they bring to areas e.g. fishing, tourism
and transport. Coastal erosion is mainly caused by hydraulic pressure,
corrosion, Corrasion and wave pounding. However, sub-aerial erosion can
also play an important role. Areas that are near to sea level and are made
from soft rock are particularly vulnerable. If coastal erosion is allowed to
happen, coastal roads, ports, holiday resorts, farmland and even whole
villages may be lost.
So how can coasts be protected?
Through Hard and Soft engineering!
.

102. Hard engineering
Hard engineering techniques are typically used to protect coastal settlements. They are used to deflect
the power of waves. These are highly visible solutions which help reassure coastal communities.
However, they are are expensive to install and maintain. In addition to this by installing hard engineering
solutions in one place this can have a detrimental effect further along the coast.
Types of Hard engineering include the following:
1. Cliff base management 7. offshore breakwaters
2. Seawalls 8. rock strongpoints
3. Revetments 9. cliff face strategies
4. Gabions 10. cliff drainage
5. Groynes 11. cliff grading
6. Rock armour

103. Types of
Management
Aims/Method Strengths Weaknesses
Seawalls Large-scale
concrete curved
walls designed to
reflect wave
energy
• Easily made • Expensive
• Life span about 30-40 years
Revetments Porous designed
to absorb wave
energy
• Easily made
• Cheaper
than
seawalls
• Lifespan limited
Gabions Rocks held in wire
cages absorbs
wave energy
• Cheaper
than
seawalls
and
revetments
• Small scale
Groynes To prevent
longshore drift
• Relatively
low costs
• Easily
repaired
• Cause erosion on downdrift side
• Interrupt sediment flow
Rock armour Large rocks at
base of cliff to
absorb wave
energy
• Cheap • Unattractive
• May be removed in storms
Offshore
breakwaters
Reduce wave
power offshore
• Cheap • Disrupt local ecology
Cliff drainage Removal of water
from rocks in cliff
• Cost –
effective
• Drains may become new lines of weakness; dry cliffs may produce
Rockfall
Hard engineering coastal management

104. Hard engineering – Sea
walls
These are the most obvious defensive methods.
Sea walls are exactly that. Giant walls that span
entire coastlines and attempt to reduce erosion
and prevent flooding in the process. They’re big,
ugly and very expensive requiring constant
maintenance so that they don’t fail. They also
produce a strong backwash in waves which
undercuts the sea wall making their long term
sustainability questionable.
Traditionally, sea walls are large flat walls however
more modern sea walls have a curved structure
that reflects waves back into incoming waves,
breaking them up and further reducing erosion.

105. Groynes
Groynes are relatively soft hard engineering
techniques. They’re low lying wooden walls that
extend out to sea. The idea of groynes is to capture
sand that moves down the beach via longshore
drift and help build up a larger section of beach in
front of an area that’s experiencing coastal erosion.
The new beach will increase the distance that
waves have to travel to reach the coast and, in the
process, they’ll lose most of their energy, reducing
their impact. Groynes are pretty effective but they
have one major drawback. Groynes will remove a
lot of the sand that’s present down-drift of the
beach which will result in a thinner beach at this
area. This, in turn, means that sections of the coast
will be more exposed to erosion down drift of the
groynes which can create new problems relating to
coastal management.

106. Gabions
Gabions are quite simply bundles
of rocks in a metal mesh. They’re
placed at the base of a cliff in an
attempt to reduce the impact of
waves on the cliff and prevent the
cliff from being undercut. They’re
not particularly effective and
they’re quite unsightly but they’re
sure as hell cheap.

107. Revetments
Revetments are concrete (or in some cases
wooden) structures that are built along the
base of a cliff. They’re slanted and act as a
barrier against waves not too dissimilar to a
sea wall. The revetments absorb the energy
of the waves, preventing the cliffs from being
eroded. Revetments can be modified so that
they have rippled surfaces, which further
help to dissipate the wave energy.
Revetments are normally successful at
reducing coastal erosion but they are
expensive to build. Once built however, they
don’t require as much maintenance as a sea
wall.

108. Riprap/Rock armour
Riprap are just rocks and stones that
have been put against the base of a
cliff. They’re similar to gabions in
their purpose but they aren’t bound
together in a mesh. This makes them
look slightly more appealing as they
blend into the environment better
however the rocks are susceptible to
being moved by the sea.

109. Breakwaters
Breakwaters are offshore concrete
walls that break incoming waves
out at sea so that their erosive
power is reduced to next to none
when they reach the coast.
Breakwaters are effective but they
can be easily destroyed during a
storm and they don’t look
particularly nice.

110. Soft Engineering
Soft engineering
techniques are low tech,
low cost solutions that
work with nature to
reduce erosion. They’re
no where near as
effective as hard
engineering techniques
but they’re far more
sustainable.

111. Type of management Aims/Methods Strengths Weaknesses
Offshore Reefs Waste materials e.g. old
tyres weighted down, to
reduce speed of
incoming wave
Relatively cost effective Long term impacts
unknown
Beach Nourishment Sand pumped from
seabed to replace
eroded sand
Looks natural Expensive and short
term solution
Managed Retreat Coastline allowed to
retreat in certain places
Cost effective;
maintains natural
coastline
Unpopular; political
implications
Do Nothing Cost effective Unpopular; political
implications
Red-lining Planning permission
withdrawn; new line of
defences set back from
existing coastline
Cost effective Unpopular; political
implications.
Soft Engineering Techniques

112. Soft engineering techniques
Beach Nourishment: This is where sand and shingle are added to a beach in order to make it wider.
This increases the distance a wave has to travel to reach the cliffs and so the wave will lose more
energy and have less erosive power when it reaches the cliffs. The sand and shingle has to be
obtained from elsewhere and is normally obtained from dredging.
Land Management: Land management is often used to help protect and rebuild dunes. Sand dunes
act as a good barrier against coastal flooding and erosion and they can be exploited as a natural
defence against the sea. In order to do so though, the dunes must be left relatively undisturbed so
boardwalks are constructed and sections of sand dune systems are marked as out of bounds to the
general public in order to reduce the erosion of the dunes by humans.
Marshland Creation: Marshland can be used to break up the waves and reduce their speed, reducing
the waves erosive power. The marshlands also limit the area which waves can reach preventing
flooding. The marshlands can be created by encouraging the growth of marshland vegetation such
as glassworts.
Beach Stabilisation: The goal of beach stabilisation is the same as beach nourishment’s goal, to
widen the beach and dissipate as much wave energy as possible before it reaches the cliffs. Beach
stabilisation involves planting dead trees in the sand to stabilise it and lower the profile of the beach
while widening the beach too.

113. Pros and Cons of Coastal
Defence!
Disadvantages ✖ Advantages ✔
• Cost of building
• Maintenance and repair
• Increased erosion downdrift due
to beach starvation or reduced
longshore drift
• Reduced access to beach during
works
• Reduced recreational value
• Smaller beach due to scour
• Disruptions of ecosystems
• Visually unattractive
• Protected buildings, roads and
infrastructure (gas, water,
sewerage, electricity services
etc.)
• Land prices rise
• Peace of mind for residents
• Employment on coastal defence
works.

114. Relationship between human activities
and coastal problems
Human Activity Agents/Consequence Coastal Zone Probs
Urbanisation and transport • Land use changes for ports/airports
• Road, rail and air congestion
• Water abstraction
• Waste disposal
• Loss of habitats and species diversity
• Lowering of groundwater table
• Water pollution
• Eutrophication
Agriculture • Land reclamation
• Fertiliser & pesticides
• Loss of habitats
• Water pollution
• Eutrophication
Tourism + Recreation • Development of land use
• Waste water disposal
• Loss of habitats
• Water pollution
• Human health risks
Fisheries • Port construction
• Fishing gear
• Fish farms
• Overfishing
• Habitat damage
• Change in marine communities
Industry • Land use changes
• Power stations
• Extraction of natural resources
• Los of habitats
• Water pollution
• Decreased input of fresh water
• Coastal erosion