LHS Higher Geography
Coastal Landscapes
Coastal Landscapes
The coast is a narrow overlap zone between the land and the sea. The sea is the main source of
energy in the coastal system and the land is the main source of rock material and sediments from
river processes, glacial processes, and slope processes (including weathering and mass
movements). Waves and tides are used to divide the coast into distinctive zones. The energy
source for most coastal erosion and transportation is from waves and to a much lesser extent, tides.
Zones of the Coast
Waves
Wind blowing across a smooth water surface wills experience some friction with the surface. This
creates small pressure differences and
eddies which instigate small ripples. As
the wind continues to blow the ripples grow
into waves. A wind blowing at 50km/h for
30 hours will generate waves with a height
of about 6m.
Fetch. The potential distance of open water over
which a wave can travel is called its fetch. The
largest waves occur where the fetch is at its
greatest. In North Devon where the fetch is over
2,800 km whereas the Norfolk coast has a fetch
of less than 200km. Remember that the
prevailing wind in the UK is from the west, so the
west coast is better for surfing than the east. The
bigger the fetch the more energy the wave
carries. Why can we surf in Lossiemouth?
Swell Waves and Sea Waves. Waves can exist
where there is little or no wind. These have been
generated elsewhere and have travelled away
from their place of origin. These are lower, flatter
waves called swell waves. Sea waves, which are
usually steeper, are generated by local storms.
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The Wave Period - This is the time taken for successive wave crests to pass a fixed point. Local
waves will usually have a period of 5-8 seconds. Swell waves may have periods of up to 20
seconds. See www.magicseaweed.com for wave periods in Lossiemouth.
Wave Energy - This is partly potential energy, resulting from the height of the wave and partly
kinetic energy caused by the wave’s movement.
Breaking waves - Waves break when they reach shallow water, this is because of the bottom of
wave starts to move in an elliptical motion due to the drag of the sea bed. As the wave breaks, the
water rushes forward translating the potential energy of the wave into kinetic energy.
Waves break in a number of ways.
In Plunging waves the crest rolls forward and downward, temporarily enclosing an air space. Such
waves are common on steep shingle beaches when waves are slow moving. The swash, or upbeach component is less important than the
backwash or down-beach component. Such
waves are often classified as destructive
waves as sediments may be moved from
the foreshore. Destructive waves dominate
in more exposed locations with longer fetch.
In spilling /surging waves, the swash is
directed up the beach so it will be stronger
than the backwash. Such waves are
sometimes classified as constructive
waves. Constructive waves dominate in
more sheltered locations.
Beaches can change depending on what
conditions they are subject to. They do not
always receive the same type of waves; this
can depend on seasons or weather
conditions. Think of the East beach in the
summer and the winter!
Tides
Tides are caused by the gravitational pull of the moon
and sun. In the UK there are two high tides every 12
hours 25 minutes. Tides can lead to strong currents,
which can scour and remove or redeposit sediments in
estuaries or other tidal environments. Tides can also
increase the effectiveness of wave processes. Most
coastal erosion, for example, takes place at high tide
when waves can easily reach the base of cliffs. Tides
can become bigger with low pressure and cause large than expect tides called storm surges.
Find out what a spring tide and neap tide is.
Breaking point of waves - Maximum erosion is caused if a wave breaks at the base of a cliff,
releasing most of its energy. This will happen at high tide, under storm conditions. Waves that break
further offshore will have their energy dissipated. This will happen on gently sloping beaches or
where there are wide wave-cut platforms or reefs.
Coastal Erosion Processes
Various processes can affect the way the coasts are eroded; the speed of erosion depends on the
geology of the area, the fetch of the waves and the direction the coast faces.
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Below the high water mark
Hydraulic Action - When a parcel of air is trapped and then compressed, either in a joint in a cliff or
between a breaking wave and a cliff, the resulting sudden increase in pressure, when repeated time
after time, can weaken, loosen, and break off fragments of rock (or sea defences).
Abrasion (or corrosion) - This is
considered to be the most effective form of
wave erosion. Waves, armed with boulders,
fragment of rock, pebbles, or even sand, hurl
their load against a cliff face, wearing away
the rock face. Where there are alternating
bands of soft and hard rocks, this can lead to
differential erosion where the less resistant
rock is removed more effectively and the
harder strata become more prominent.
Attrition - Wave attrition affects the
detached material produced by other
erosional processes. Particles collide
resulting in both the reduction in size and
increased rounding of fragments. Most
rounding takes place in the wave break
zone. Effective attrition of larger particles is
particularly important, otherwise the sea
would not be able to abrade and transport
sediment away effectively.
Corrosion/solution. Solution is particularly
important on limestone by carbonic acid in
seawater. Biological activity can assist the
process of solution as the secretions of algae attack rocks. The corrosion areas can extent above
the water line due to sea spray.
Above the high water mark
Sub-aerial Processes - Cliff recession occurs primarily as a result of the mass failure. The marine
processes can only affect the base of a cliff creating a wave-cut notch. This increases the cliff’s
gradient or undermines it. The rocks of a cliff face will be affected by a range of weathering and
slope processes, which weaken rock and eventually result in its failure. These processes will
involve, throughflow and runoff and atmospheric influences including rainfall, frost and wind.
The main physical weathering processes include frost shattering, pressure release, salt
crystallisation and mechanical biological weathering.
The main chemical weathering processes include oxidation, hydration, hydrolysis, carbonation,
solution and chelation depending upon the rock type.
Mass movement processes include soil creep, earthflows, mudflows, rockslides (including land
slips, rotational landslides or slumping) and rockfalls. Again this all depends on the rock type and if
it is a soft or hard coast line.
Erosion of most cliffs is not a regular, steady process. Instead it is a result of infrequent catastrophic
events by which large fragments of the cliff slope will fail.
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Factors Affecting Coastal landscapes
Concordant and Discordant Coasts
Coastlines are very varied and it is possible to classify them in different ways. One way is on the
basis of geological structure and trend of the
coastline, particularly where there are
alternative bands of resistant and less
resistant rock. Two examples — concordant
and discordant — are distinguished:
Concordant Coasts
These occur where the coastline runs parallel
to the geological trend. This can be seen in
south Dorset around Lulworth Cove.
Discordant Coasts
These are the opposite of concordant. They
occur where the coastline cuts across the
rock structure. An example can be seen in
south Dorset at Studland Bay and Swanage.
Land forms mainly resulting from erosion
Headlands and Bays
Headlands are more resistant types of rock that protrude out into the sea, bay are usually the softer
rock that erode away quicker.
Wave Refraction. The approaching wave crests are
perpendicular to the general trend of the coastline.
As the approaching waves (shown by the position of
their crests) move nearer to the shores of the
headland, they begin to slow down and increase in
height as they meet shallow water. In the bays, the
waves continue unimpeded and so move ahead of
the fragment of the same wave approaching the
headland.
The end result is that the wave crests attempt to
align themselves with the shoreline. Segments A and
B have the same width (and therefore equal amounts
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of energy) in deep water. The orthoganals, drawn at right angles to the wave crests show that, by
the time they reach the shore, the energy of segment A is concentrated on a length of coast about
1/3rd of the length of segment B, where the energy is more dissipated. This distortion or refraction
of waves focuses wave energy onto headlands, islands and dissipates it in bays leading to the
construction of a bay-head beach.
Cliffs
The actual profile and height of cliffs varies greatly. There are many reasons for this, but the
following three factors are very significant.
The hardness of rock: Soft rocks are less resistant to marine erosion, there bases are easily
undercut so slumping occurs. Generally they are low and have gentle, convex slopes. They are
usually found in the SE of Britain such as East Anglia and are often made up of boulder clay. Hard
cliffs however are usually more resistant to marine erosion. They are formed from rocks such as
granite, basalt, limestone, sandstone
and chalk, they are usually high and
steep and found along the north and
west of the Britain.
Rock structure: Horizontal strata
and vertical joints common in
limestone and flaggy sandstones e.g.
Orkney, result in the formation of
steep cliffs, as do the hexagonal
columns on Staffa and the Giants
Causeway in NI. When the rock
strata dip towards the sea, the cliff
profile will overhang: where they dip
landwards, a sloping cliff results.
The balance between mass wasting and the rate of base erosion: if wave energy is strong,
debris at the foot of the cliff will be removed and the cliff base will be actively eroded. This
encourages steep, even vertical cliffs. If however, wave energy is weak e.g. because of a sheltered
location, debris accumulates and protects the cliff from wave erosion.
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Wave-Cut Platforms
Weaknesses, e.g. joints and small faultlines in the intertidal zone of hard rock cliffs are progressively
undercut by wave erosion at their base to form a wave-cut notch (see Figure 4.8 1. This notch is
steadily weakened and enlarged, and in the course of time, the overhanging cliff collapses. As these
processes are repeated, the cliff retreats, exposing at its base a gently sloping, rocky surface called
a wave—cut platform (sometimes called shore platforms). Typically, the upper part of such
platforms is exposed at low tide as a rocky foreshore — usually with pools, rounded rocks and small
ridges of more resistant rock. With the flow
and ebb of the tide across its surface the
platform is abraded by the sweep of sand,
shingle and pebbles across it, while swirling
action encourages the formation of rock
pools and poi holes. As the cliff continues to
retreat and the platform grows ever wider,
more wave energy is spent passing through
the increasingly wide belt of shallow water
at low tide. Eventually, wave attack on the
cliff base will be less powerful, limiting any
further growth of the wave-cut platform.
Undercutting and cliff retreat slowly decline,
and sub-aerial processes weathering and
mass movement) become more important
resulting in a gentler cliff profile.
Caves, Blowholes, Natural Arches, Stacks and Geos
On hard cliff faces, sea caves develop by- wave erosion, attacking lines of weakness, such as joints
and small faultlines. These weaknesses allow a faster rate of erosion that steadily creates and
enlarges caves. Wave erosion, especially hydraulic action, smoothes the lower walls of sea caves
while their upper walls and roofs are generally
more angular as a result of rock falls.
Continued erosion of a vertical joint at the back
of a sea—cave may mean the collapse of its
roof; resulting in a blow-hole. A blow-hole is a
funnel- shaped depression, linking the cliff top
with the sea- cave. As strong waves surge into
the cave, the air is compressed and columns of
spray are forced upwards through the funnel. A
gloup is an alternative name for a blow-hole in
Scotland.
• If sea-caves form in a rock weakness linking
both sides of a headland or promontory, a
passage is cut through to form a natural arch. As
with sea-caves, the eventual shape of such
landforms is influenced by the dip of the bedding
planes in the rock and its hardness. Notable
examples include Durdle Door (limestone),
Dorset, and the Bow Fiddle (quartzite),
Portknockie
• As wave action continues to enlarge such
marine arches, the keystone arch will eventually
collapse and the landform becomes a stack. A
stack has been defined as a freestanding
pinnacle of rock. Such a feature may stand for a
few thousand years, but continued erosion of its
foundations and weakening of its upper parts will
reduce it to a stump. Famous examples include
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The Needles (chalk), Old Harry and Old Harry’s Wife (chalk), and The Old Man of Hoy (sandstone)
— the highest British example — 137 metres above sea level.
• A related erosional feature is a geo. Basically it is a small, narrow, steep—sided channel in a seacliff which has been worn by marine erosion along a line of weakness such as a joint in the rock.
Originally it was a narrow cave but, at various stages the roof has collapsed, leaving the inlet. Such
landforms are particularly found in the hard cliff coastlines of northern Scotland, the Western Isles
and Northern Isles.
Coastal Transportation
The shape of a coastline is influenced not only by erosion but also by the transportation and
deposition of material. Waves and currents (generated by waves and tides) move countless tonnes
of material up and down shores and along the coast. The rate of transportation depends on the
waves and currents, and the size of the particles. Usually transported sediments range in size from
the finest silts, to sand, to shingle, to pebbles.
Movement Up and Down Beaches
Earlier, we saw that waves may be classified as either constructive or destructive. Constructive
waves are flat and low, and their swash moves material such as sand, shingle and pebbles up the
beach. One result is the formation of a berm — a shingle ridge which marks the limit of the swash at
high spring tide. Particularly strong storm waves throw larger pebbles beyond the berm to form a
stranded storm beach. Destructive waves are steeper and higher, and their backwash sifts out and
carries finer material, especially sand, down the beach.
Longshore Drift; Waves seldom approach a
beach at right angles, instead oblique swash
waves push material diagonally up the beach,
and the returning backwash drags much of
the material straight back down. Through
time, material is moved along the shore in the
direction of the prevailing wind. This lateral
movement of material is called Iongshore
drift. The actual rate and direction varies
according to the strength and reliability of the
prevailing wind. In general, in Britain drift
tends to be southward on the east coast,
northward on the west coast, and eastward on
the south coast. Seasonal changes in wind
direction, however, can cause material to drift
to and fro.
Beaches are an important resource, particularly in seaside resorts. Frequently, resorts erect bafflers
(of timber or steel) called groynes. These allow sand and shingle to build up on one side of a groyne
as an effective way of conserving beach sediments. One problem, however, is that the downside
stretch of shoreline is now deprived of material, and this may result in increased erosion. It is a
reminder that change (planned or unplanned) in one stretch of coastline results in change in
another.
Coastal Deposition
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Transportation of material ends when the coastal environment becomes more sheltered. Currents
weaken, and as they are no longer able to continue carrying sediment, some of it is deposited in the
form of distinctive coastal landforms. There are three main sources (or inputs) for such sediment —
rivers, cliffs and the sea bed. By far the most important input (around 85 per cent) comes from
rivers, and is mainly deposited (stored) in depressions on the continental shelf Only about 10 per
cent comes from cliff erosion in many areas, while the smallest input is from sea bed erosion, which
was particularly important at the end of the Ice Age but less so nowadays. Another source of
sediment comes from the crushed shells (skeletal remains) of marine organisms, particularly
important in the lime-rich, machair shorelines of North-West Scotland and, especially, the Western
Isles. (Machair is the name given to the flower rich, grassy meadows that thrive on the low lying,
alkaline-rich coastal plain.)
Coastal Landforms Mainly Resulting from Deposition
Depositional landforms result when the
amount of sediment that has accumulated
exceeds the amount which is being lost.
Generally this occurs in sheltered areas and
where there is an adequate input of
sediment. The resulting landforms include
beaches, spits, bars, tombolos and dunes.
Beaches
Beaches are the depositional feature with
which we are probably most familiar. It is a
shoreline formed from unconsolidated sands
and/or shingle. At the landward edge of
beaches there may be soft or hard cliffs, or
belts of sand dunes.
• Bayhead beaches are typically small,
crescent- shaped, and form when sediment
(usually sand and/or shingle) accumulates in
a bay or cove between two protective
headlands. Such protection means relatively little change in the input or output of sediment, thereby
sustaining the shape of the beach. Lulworth Cove beach is such an example.
• Lateral beaches are usually longer, develop along straight coastlines, and are aligned in the
direction of prevailing winds. Sustaining such beaches involves a regular input of sediment from
longshore drift, and from erosion at the back of the beach under storm conditions. Beaches along
the Yorkshire’s Holderness coast between Bridlington and Spurn Head have a large input from the
rapidly retreating soft cliffs of glacial till, but beach defences in the form of groynes are important at
resorts such as Hornsea.
• The upper beach is often composed of coarser sediment, frequently shingle, and tends to have a
slope of 1O°—20°. Above the level of the highest spring tides, there is a storm beach, a ridge with
rounded boulders deposited under exceptionally
strong waves. Below it is a berm — a ridge of
shingle marking the high tide limit of swash
activity by constructive waves. Cut into the
shingle are cusps — small, regular
embankments, up to several metres in size.
• The lower beach is usually formed from sand
or even mud, and has a very gentle slope of 2° or
less. Typically, it is cut by small channels
draining to the sea, frequently with small river
terraces that form as the tide ebbs. Small ridges,
ripples and runnels (depressions) also develop
parallel to the shoreline.
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Spits
Spits are generally low ridges of sand and/or shingle that extend, finger-like, from the shore across
a bay or a river estuary. They grow out from the coastline so long as the input of material from
longshore drift exceeds the amount removed by waves and tidal scour. Two examples illustrate the
growth of spits.
• Located on the Suffolk coast, Orford Ness is a relatively straight spit formed from shingle ridges,
and which stretches a distance of 15 km
south and southwest from the town of
Aldeburgh. Over many years, it has
extended southwards, though not without
interruptions to its growth as a result of
breaches by the sea. For much of its length,
its ridges deflect the River Alde and River
Ore southwards, so that they flow parallel to
the spit, only gaining direct access to the
North Sea at North Weir Point. The growth of
Orford Ness depends on a plentiful supply of
shingle. Most came from the soft coastal
cliffs of Suffolk, and glacial deposits on the
North Sea floor. Another feature often
associated with spits is shown on Figure
4.96 — the development of salt marsh in the
sheltered area between the river and the
spit. Such marsh, and indeed Orford Ness
spit itself are threatened by rising sea levels.
Bars
Bars are related depositional features and
come in several varieties. Baymouth bars
occur where a spit grows across the entrance to a bay or estuary, and encloses a sheltered
freshwater lagoon behind it. Examples can be seen at Slapton Ley in Devon, and the Loe Bar,
formed from shingle, near Porthieven, Comwall. In Orkney, baymouth bars are called ‘ayres’, and
examples include the Peedie Sea at Kirkwall and Long Ayre at Inganess Bay to the east. Such a
situation occurs when there is no major river (as at Dawlish) flowing strongly into the sea at the
embayment.
Off-shore bars form at the mouth of estuaries and rivers, and are sand or gravel banks which are
exposed only at low tide. They are potentially hazardous to shipping because of the action of
longshore drift which
encourages their migration.
Barrier beaches, unlike offshore bars, are not
submerged by high tides. If
they are high enough to
permit the growth of sand
dunes, they are called
barrier islands.
Both barrier beaches and
barrier islands are
separated from the
mainland by an open
lagoon in which salt
marshes may develop. Two of the largest examples of barrier islands in the British Isles are in
Norfolk: Blakeney Point and Scolt Head Island (Figure 4.99). It is believed that Scolt originated as a
barrier beach which was thrown up by wave action as sea level rose at the end of the Ice Age.
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Tombolos
Tombolos are spits of sand and/or shingle which connect the mainland to an island. Compared to
spits and bars, they are not such common depositional landforms. St Ninian’s tombolo is around
500 metres long, it is formed mainly from sand on top of a gravel base, and links the south-west
Shetland Mainland with the small off-shore island of St Ninian’s Isle. Prevailing westerly waves
approaching St Ninian’s Isle are forced around the island and meet in its sheltered easterly lee side.
As the waves lose their energy, they deposit their load from both the north and the south, and build
up the connecting spit. The flow of sediment is sustained by sandy deposits in the bays to the north
and south of the tombolo. Throughout the year, the tombolo’s size fluctuates: smaller in winter, and
larger in summer. Other examples include: the Scilly Islands, where some of the larger islands have
been formed by the linking of smaller islands by sand tombolos; and the Welsh coastal resort of
Llandudno, whose site mainly occupies a broad tombolo.
Sand dunes and Salt Marshes
These are important features of landscapes of coastal deposition. This is because wind (aeolian)
processes rather than marine processes, along with differing types of vegetation play such a
significant role in the formation of sand dunes. On the other hand, waves and currents have played
an important part since the end of the Ice Age in ensuring a plentiful supply of sand, critical for dune
growth, a supply that is now diminishing except at the mouth of sediment-laden estuaries such as
the Tay (see the study of Tentsmuir dune complex pages). Waves can also be very destructive and
destroy dune complexes.
Salt marshes are vegetated areas that develop at sheltered estuaries, and in areas protected from
strong wave action by spits and bars. In Britain,
salt—marsh areas are widespread with significant
areas found around the Solway Firth,
Morecambe, Bay, the Severn, Exe and Dee
estuaries, and the Norfolk coast e.g. Scolt Head
Island
• Thin layers of mud and silt accumulate in
sheltered areas to form mudflats, exposed at low
tide
• Green algae and salt-tolerant (halophytic) plants
e.g. Salicornia and Spartina colonise the mudflats
• Sediment is spread when high tide covers the
plants, and is retained as the tide ebbs. Channels
are cut as the sea water recedes (see page 162)
• Gradually the the level of land rises at up to 10
cm a year; the plant cover becomes denser and
more varied; and the channels deepen and form
an intricate dendritic drainage pattern of creeks that fill at high tide. Salt—marshes may be of value
to people as nature reserves (for birds and plantlife) e.g. Dawlish Warren, or as SSSIs. They may
be grazed by sheep and cattle, or have been reclaimed for farmland e.g. the southern part of Scolt
Head.
Changes in the Relative Levels of Land and Sea
As we have seen, coastlines are continually changing as a result of erosion, transportation and
deposition. Certain coastal landscape features have resulted from longer term changes in sea level
over the last 20 000 years (since the Pleistocene Ice Age). Massive quantities of sea water were
locked up in ice sheets and glaciers, resulting in a fall in sea level of over 100 metres. There was a
global rise in sea level at the end of the Ice Age as the ice melted. Such changes in sea level are
refered to as eustatic changes.
A related change resulted from the vast weight of ice (several kilometres thick during the Ice Age)
locally depressing the earth’s crust. Once the ice melted, the land recovered, resulting in a local rise
in the level of the land and a relative fall in sea level. This type of uplift is called isostatic uplift.
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The landforms resulting from such changes in the relative levels of the sea and the land may be
broadly classified as those which have emerged and those which have been submerged.
Coastal Landforms of Emergence
Differences in ice thickness meant that the amount of isostatic uplift varied considerably in different
parts of Scotland. Where the land rose at a rate faster than rising sea levels, relict shorelines form
with ‘fossil’ features such as raised beaches, raised wave cut platforms, raised deltas, raised
estuary mudflat deposits (called carse in Scotland), and abandoned clifflines with caves and stacks.
Examples of such raised shoreline features are found along much of Scotland’s coastline.e.g. Arran
Traditionally, such raised shoreline features were believed to be found at three levels: 7.5 m, 15 m
and 30 m. In reality, this is too simple a picture because of varying rates of post—glacial eustatic
and isostatic change. Raised beaches vary in height and are gently tilted. Interestingly, isostatic
uplift is still happening in Scotland, but it is now being overtaken by a rise in sea—level.
Coastal Landforms of Submergence
The most common coastal features caused by eustatic rises in sea level are drowned valleys. There
are two main types in the British Isles, rias and fiords. Ria is a Spanish word used to describe a
submerged coastal valley resulting from a rise in sea— level. Rias are found in north-west Spain,
south-west Ireland e.g. Bantry Bay, south—west Wales e.g. Milford Haven, and south—west
England, and were formed by the drowning of the lower part of an unglaciated river valley.
A typical ria:
• has a ‘V’—shaped cross-section
• has fairly steep, though not particularly high, sides
• has a long profile that deepens towards its mouth
• has a branching pattern as the tributaries have also been drowned
• is frequently silted with very thick marine and river sediments unless there is a strong tidal flow.
A Fiord, on the other hand, is a long, deep, narrow inlet of the sea, bounded for the most part by
steep mountain sides. Fjords formed when glacial troughs were drowned by the relative rise in
sea—level after the melting of the Pleistocene ice. In Britain, the best examples are the sea-lochs of
Western Scotland, though their valley sides are not so steep as those of Norway and Iceland.
Shetland has gentle-sided versions called voes.
A typical fiord/sea loch:
• has a ‘U’-shaped cross-section
• has very steep, high sides
* has a long profile which is deepest in the central stretch, with a shallow entrance called a threshold
at its mouth
• may have tributaries which join as waterfalls from hanging valleys
• may have a delta at its head.
Coastal Landscapes: Economic and Social Opportunities
For Industry and Power Generation
Attracted by locational advantages such as the availability of cheap, level estuarine land e.g. at
Grangemouth, deep sheltered natural harbours for large vessels e.g. Milford Haven, and ease of
import of bulk raw materials and fuels and export of manufactured goods, coastal sites have long
attracted industries. These can range from shipbuilding (now drastically reduced) e.g. Clydeside, to
coastal integrated iron and steel works e.g. Port Talbot, to oil refineries and petro-chemical works
e.g.. Grangemouth and Teeside. Coastal sites also are valued for energy generation: power stations
— thermal e.g. Cockenzie and nuclear e.g. Torness; as well as renewable sites for wind, wave and
tidal power.
For settlement
This dates from the seasonal camps of small groups of the earliest hunter—gatherers some 6000
years ago to the millions of people in the British Isles living nowadays on or near the coast.
Settlements of varied size and function have grown up (and in some cases declined) and can
include fishing villages and ports (ferry ports, container ports, naval ports and oil terminals), some of
which developed into large cities e.g. Bristol, Liverpool, Dundee and Aberdeen. Some large coastal
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holiday resorts also had small beginnings: Blackpool, for example, started life as a fishing village but
its rapid growth from the 19th century was encouraged by factors such as the presence of beaches,
the increased popularity of sea bathing, paid holidays, and the growth of railway links with the
industrial areas of Lancashire. Coastal resorts of varying size such as Aberdour and Bournemouth,
continue to be attractive as dormitory settlements and for an increasing number of retirees with
consequent pressure on land resources for housing and related infrastructure e.g. sewage and
waste disposal. Overall, accessible and attractive coastal stretches are being built up.
For Tourism and Recreation
In spite of the package holiday revolution from the 1960s onwards, coastal areas in Britain still
attract millions of people for annual holidays, traditional day trips and Bank Holidays, and,
increasingly, for shorter breaks including educational excursions, business trips, and special—
interest trips e.g. geology. wildlife etc. Coastal resorts and beaches such as Lulworth Cove are
significant ‘honeypots’ attracting thousands of visitors with resulting crowded car parks, unsightly
caravan parks and chalet complexes, and pressure on footpaths. Coastal ‘links’ golf courses are
also popular features, and occupy raised beaches and coastal dunes. Long distance coastal
footpaths attract large numbers e.g. the South West Coast Path, Britain’s longest National Trail, has
over a million visitors per year with resulting erosion along certain stretches. Coastal waters can
also be congested: the sheltered waters of Hampshire are perhaps the busiest waters in Britain for
yachting, while power boating, jet-skiing and wind surfing are also popular. Collision hazards are not
unknown in stretches of water such as the Solent with potential risks of oil pollution and possible
impact upon. coastal Nature Reserves and SSSIs.
For Scenery and Conservation
Management of Britain’s coastline takes various forms and includes: the 155 km long Dorset and
East Devon World Heritage Site, popularly known as the ‘Jurassic Coast’, the Pembroke National
Park, AONBs (Areas of Outstanding Natural Beauty) e.g. East Devon, and Country Parks e.g. John
Muir Country Park, East Lothian. Such bodies have different management powers but generally
they are charged with two apparently incompatible objectives: (i) conserving the scenic features
such as distinctive coastal landforms and (ii) allowing public access to such areas for a range of
recreational purposes but without damaging the environment.
Other Uses
Relatively remote coastal areas, often attractive to groups such as walkers or bird watchers, are
also useful for military purposes e.g. as firing ranges on the Solway Firth. Sparsely populated
coastlines are also suited to coastal superquarries, particularly along hard rock coastlines.
Glensanda superquarry on Loch Linnhe produces some five million tonnes of granite annually, and,
with a workforce of 160, is a welcome boon to the local economy. Local pressures from
conservation interests can prevent such developments, as was the case in the much-debated
proposal for a superquarry at Lingerabay on Harris. Such demands for a wide range of land uses
has put a great deal of pressure on stretches of Britain’s coastline, posing problems for local,
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LHS Higher Geography
Coastal Landscapes
regional and national planners. This is a situation that will be increasingly exacerbated by the
longer—term related threats of rising sea levels and increased erosion, resulting from global
warming. It also has to be acknowledged that, in spite of the economic and recreational value of a
coastal site (e.g. a links golf course threatened by erosion), attempts to protect them using remedial
measures may be futile. For one thing, there is the cost (e.g. of a coastal barrier); for another,
solving the problem on one piece of shoreline creates problems further along the coast. That is why
a good knowledge of the natural dynamics of coastal erosion, transportation and deposition, and
how they interact, is so useful in planning for the future.
Coastal Defences
Cliff Protection. Where coastal erosion threatens buildings or land considered to be of value,
coastal defences are used which can in themselves lead to further problems, particularly if sediment
supply and movement is disturbed.
Groynes. Wooden groynes are probably the most
familiar way in which people try to manage
coastal processes. These reduce longshore drift and
help to accumulate beach sediments. This can
protect cliffs from erosion. At West Bay, larger
groynes called bastions are used. These are more
robust, but serve much the same purpose. In
Christchurch Bay in Hampshire, they are called
strong-points. More conventional wooden groynes
are used at Milford-on-Sea.
Sea walls are quite effective but expensive. Curved
sea walls reduce wave reflection and wave energy is
deflected. The walls are impermeable so, at the base
of sea walls, scouring by wave activity can
undermine the wall, increasing maintenance costs.
Rock armour (rip-rap) consists of large boulders of
hard rock. Their irregular surfaces dissipate wave
energy effectively. Their disadvantage is that they
create a barrier for users of the beach and they can
be unsightly. In heavy storms, boulders can be
displaced. These are used at Westward Ho! to
protect the base of the sea wall from scour.
Gabions are wire cages with pebbles or rocks can
be used to protect the base of a cliff (used near
Overstrand in North Norfolk) or they can be built into
groynes to reduce longshore drift. These were
ineffective at Westward Ho! as the Pebble Ridge spit
retreated leaving them stranded. They also became
an eyesore and a safety hazard as the steel cages
rusted.
Concrete revetments are aprons of concrete laid on
a graded slope to dissipate wave energy. Cheaper
than sea walls but can be displaced by waves. A
stepped variety is used at the base of the sea wall at
West Bay in Dorset.
Wooden revetments are open structures designed
to absorb wave energy while allowing the sediment
to pass through, thus allowing the accumulation of a
protective beach. Not used in North Devon or Dorset
but widely used on the North Norfolk coast. They
have a short life and
require regular maintenance.
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LHS Higher Geography
Coastal Landscapes
A widely used alternative to hard engineering is to use beach replenishment. The beach is fed
artificially with material from another locality or dredged from the seabed, or from down drift where
sediments are accumulating. This has been used at Westward Ho! but engineers have found that
the down-drift supplies are running out, as quantities of the replenished beach material are lost to
the offshore zone.
Dredging. Dredging is used, either to maintain deep water channels for shipping or to obtain
aggregate for the construction industry. Dredging can upset the balance of sediment within a littoral
cell. This was demonstrated in 1917 when the South Devon village of Hallsands was largely
destroyed by a storm. Contractors building the Devonport Naval Dockyard removed the shingle
beach that had previously protected the village. The beach was lowered by 65m when 660,000
tonnes of gravel were removed. The beach was probably a relict feature deposited as sea levels
rose about 6000 years ago. Up to 6m of cliff erosion took place at Hallsands between 1907 and
1957.
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