Holderness Coastline

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Holderness Coastline
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Aims and objectives

• To understand that coastlines work as a system
  and are dynamic.
• To understand the processes of coastal erosion
  and how these shape the Holderness Coastline.
• To discover how the coastline is being protected.
• To gain in depth knowledge of the Holderness
  Coastline, looking at Flamborough Head, Hornsea,
  Mappleton and Spurn Point.
• To start and complete a geographical enquiry into
  the Holderness Coastline.

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Location HoldernessCoastline
The Holderness Coastline is located on the North
East coast of England.
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Erosion of the Holderness Coastline

• There are three main processes at work along
  any stretch of coastline. These are
• EROSION
• TRANSPORTATION
• DEPOSITION
• Erosion is occurring at a rapid rate along
  the Holderness Coastline and this is creating
  many problems.

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Focus areas along the Holderness Coastline

• The Holderness Coastline of the East Riding of
  Yorkshire is suffering from the worst coastal
  erosion in Europe. In the last 2000 years the
  coastline has retreated by almost 400m and since
  Roman times over 30 villages have disappeared
  into the sea between Bridlington (just south of
  Flamborough Head) and Spurn Head.
• Although large towns such as Hornsea are
  protected by sea walls they may eventually be
  left cut off at the end of a long peninsula.
• About a million years ago the Yorkshire coastline
  was a line of chalk cliffs almost 32km west of
  where it now is. During the Ice Age deposits of
  soft boulder clay (or till) were built up against
  these cliffs to form the new coastline. It is
  this soft sand and clay which is easily eroded by
  the action of waves.

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What is erosion ?

• Erosion is the process by which coastline rocks
  are broken up by the action of the sea and
  transported out to sea or along the coast by
  waves and the wind.
• As the wave approaches shallow water near to the
  coast, its base is slowed down by friction
  against the sea bed. The top of the wave will
  move faster, increasing in height and eventually
  breaking onto the beach. If it has a strong
  backwash it will drag large amounts of material
  down the beach.
• The Holderness coastline is eroding at a rate of
  1-3 metres per year.
• Coastal erosion can take a number of forms
• Seawater can compress air into cracks in rocks.
  When the air escapes it does so under pressure
  and shatters the rock (hydraulic action)
• Large waves throw beach material against the
  cliffs - a process known as corrasion.
• In a process known as attrition waves cause rocks
  and pebbles to crash into each other, causing
  them to break up.
• Certain types of coastal material, such as chalk
  are slowly corroded by acids dissolved in the sea
  water.

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How do waves erode the Holderness Coastline ?
Constructive waves have a strong swash (movement
up the beach) and a weak backwash (movement back
down the beach).
Destructive waves have a weak swash (movement up
the beach) and a strong backwash (movement back
down the beach).
The Holderness coast is subject to the full force
of the waves from the north sea with minimal loss
of energy before they reach the cliffline.
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Journey along the Holderness Coastline (from
north to south)
This lesson we will take a journey along the
Holderness coast from Flamborough Head, stopping
at Hornsea, Mappleton and ending at Spurn
Point. Along the way we will be looking at
coastal features, defences, processes and the
impact the sea has on the people that live there.
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Holderness journey fact file

• The Holderness Coast is one of Europe's
  fastest eroding coastlines. The average annual
  rate of erosion is around 2 metres per year. The
  main reason for this is because the bedrock is
  made up of till. This material was deposited by
  glaciers over 18,000 years ago.
• The Holderness Coast is a great case study to use
  when examining coastal processes and the features
  associated with them. The area contains 'text
  book' examples of coastal erosion and deposition.
  
• The chalk of Flamborough provides examples of
  erosion, features such as caves, arches and
  stacks.
• The soft boulder clay underlying Hornsea provides
  clear evidence of the erosional power of the sea.
  
• Mappleton is an excellent case study of an
  attempt at coastal management.
• Spurn Point provides evidence of longshore drift
  on the Holderness Coast. It is an excellent
  example of a spit.

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Geology at Flamborough Head

• The most striking aspect of Flamborough Head
  are the white chalk cliffs that surround it. The
  chalk lies in distinct horizontal layers, formed
  from the remains of tiny sea creatures millions
  of years ago. Above the chalk at the top of the
  cliffs is a layer of till (glacial deposits) left
  behind by glaciers 18,000 years ago, during the
  last Ice Age. As the cliffs below are worn away
  by the action of the waves, the clay soil often
  falls into the sea in huge landslips.

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Structure of Chalk Flamborough Head
The sea attacks the coast around the headland in
two ways. Waves beat against the vertical cliffs
and, at the high water line, weak points in the
chalk are worn away into caves. The weakest
points are where vertical cracks or fault lines
have appeared in the horizontal beds of chalk. At
places on the cliffs where the chalk juts out,
these caves are worn away into rock arches. If
the top of an arch collapses, the result is a
pillar of chalk cut off from the rest of the
headland - this is called a stack. Flamborough
Head has many caves and arches, as well as a few
stacks. The process of erosion that has created
them can take hundreds of years to do its work.
Joint
Bedding plane / fault line
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Flamborough Head Coastal featuresErosion of a
Headland
Caves
Arch
Stack
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Hornsea

• Location
• A 2.9km stretch of shoreline fronting the town of
  Hornsea. A high density urban development
  containing residential and various tourist
  related properties, Hornsea's local economy is
  dependent on tourism and recreation as well as
  incorporating a small fishing industry.
• Geology
• Hornsea lies upon unconsolidated till. This
  material was deposited by glaciers during the
  last ice age 18,000 years ago.
• Coastal Features
• The groynes on Hornsea beach ensure wide and
  relatively steep beaches. The beach material is
  made up of sand and shingle.

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Hornsea

• Coastal Management
• The position of the coastline at Hornsea has
  been artificially fixed since existing coastal
  defences were erected in the early 1900s. Hard
  defences in the form of a concrete seawall and
  timber groynes afford protection and an on going
  refurbishment programme ensure this has
  continued. More recently a stone gabion has been
  erected to the south of Hornsea. This helps
  protect the caravan park. Beach material is being
  transported south along the Holderness Coast by
  longshore drift. In Hornsea sand has accumulated
  where protection exists. This is because the
  groynes provide a barrier to sediment
  transportation. This has reduced erosion within
  the section but increased rates are evident
  further south.

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Hornseas Coastal defences
Wooden groyne notice the difference in sand
heights.
Wooden groynes and rock wall.
Gabions.
Concrete sea wall, protects the caravan park.
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Mappleton

• Location
• Situated approximately 3km south of Hornsea lies
  the village of Mappleton. Supporting
  approximately 50 properties, the village has been
  subject to intense erosion at a rate of 2.0m per
  year, resulting in the access road being only 50m
  from the cliff edge at its closest point.
• Geology
• Mappleton lies upon unconsolidated till. This
  material was deposited by glaciers during the
  last ice age 18,000 years ago.
• Coastal Features
• The two rock groynes at Mappleton have helped
  develop wide and steep sandy beaches.

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Why protect Mappleton ?
In 1990, Mappleton was under threat from losing
30 houses along the coast of Holderness. Its main
road, the busy B1482, wouldve disappeared into
the sea and would be very expensive to rebuild.
So, a coastal management scheme was set up.
Blocks of granite were imported from Norway so
two groynes could be built. This would trap the
beach sediment that is being eroded away due to
longshore drift. This would then absorb some of
the energy from the waves so less energy would be
directed on the cliff's side. This would reduce
erosion.
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Mappleton

• Coastal Management
• In 1991 two rock groynes and a rock revetment
  were built, as a consequence a substantial beach
  accumulated between the groynes halting erosion.
  However, further south the rate of erosion has
  increased significantly. This is because material
  which is being carried south is not being
  replaced (it is trapped within the groynes).
  Therefore there is no beach to protect the
  cliffs. Even during a neap tide ( a tide which is
  30 less than the average tidal range) the sea
  reaches the base of the soft cliffs and erosion
  occurs.

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Mappletons coastal defences
The rock groynes prevent longshore drift and
encourage deposition of sediment. This creates a
beach and a natural barrier that prevents waves
from breaking directly on the cliff base. This
therefore prevents erosion.
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However, further south towards Withernsea erosion
has been increased Why ??
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No beach, no defence !
The process of longshore drift can no longer
transport material along the coastline to be
deposited at the base of the cliffs. All the sand
has gathered at Mappleton, this leaves the
glacial till cliffs exposed to the sea. The
rates of erosion just south of Mappleton have in
places been as much as 10 metres per year. People
have lost their homes, farmland and livelihoods.
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Spurn Point

• Spurn Point is a narrow sandy coastal spit
  aproximately five kilometers long. It is located
  on the south-eastern tip of the Holderness plain
  which forms the northern banks of the Humber
  estuary.
• Spurn Point is a feature of coastal deposition
  and reguires a constant supply of sediment from
  the process of longshore drift.

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Spurn Point
The strategic position of the sand spit, guarding
the entrance to a major waterway lead to its use
as a position for shipping beacons and
lighthouses. Historical accounts of settlements
and lighthouses, particularly accounts of their
destruction and the break up of the spit have
enabled us to discover that over the last 1000
years there have been five 'Spurn points'. Each
spit has grown until it has become unstable, been
destroyed and then rebuilt slightly to the west
of the former one, the cycles lasting
approximately 250 years. The current spit is
nearing the end of the cycle, and despite
considerable coastal defences the neck is in
continual danger of being breached.
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Why protect Spurn Point ?
Spurn Point protects many wildlife habitats and
ecosystems which have developed behind the spit.
Spurn Point itself has essential services such as
the Lifeguard station. Many wooden groynes and
other coastal defences have been built to protect
and preserve the spit. However if sediment is
prevented from reaching Spurn Point the
consequences could be immense.
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Implications of protecting the Holderness
Coastline

• Saved the village and road. Mappleton row has a
  beach and a growing tourist trade. But - local
  downstream farmers are losing land at an even
  quicker rate. The farmers profits are being
  threatened.
• Withernsea, a large resort town, has now to spend
  millions to build toe revetment sea defences to
  protect the town. This is very costly.
• Industry at Easington is being threatened with
  the gas terminals coming too close to the sea.
  This is not only dangerous but could force the
  gas terminal to close with the loss of 1000s of
  jobs
• Essential services at Spurn Point (Coastguard,
  Lifeboat) are now threatened as the spit is being
  starved of material.
• Wildlife to the rear of the Spit is losing a good
  migrating spot. These species are seen even less
  in the area.
• Long term effects on King' s Lynn and Amsterdam
  have yet to be analysed but they may need to take
  on extra sea defences

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Summary

• The Holderness Coastline is shaped by erosion,
  transportation and deposition. These work
  together to create a variety of coastal features
  (caves, stacks, beaches, spits).
• Erosional processes (corrasion, corrosion,
  attrition and hydraulic pressure) produce some
  interesting features especially at Flamborough
  Head. They also cause many problems further down
  the coast where the geology is less resistant
  (Mappleton, Hornsea).
• Coastal defences include wooden groynes, rock
  gabions, concrete sea walls and the beach.
  Developing these in certain areas however has
  important implications further along the coast.
• However careful planning is needed to ensure that
  the whole coast is managed in the most
  sustainable manner.
• Study the guide for the coastal landscape and
  process enquiry carefully, this will be an
  assessed piece of work.

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Now, if theres time watch the video shifting sand
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Re draw map slide 3 and 5Slide 7Same map from 3
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