Holderness Coast: A multi-use area Why have coastal areas

Holderness Coast: A multi-use area
A multi use areas is n area which offers a range of social,
economic and environmental activities.
Flamborough Head – stunning scenery and birds
attracts tourists to visit.
Bridlington – provides retirement homes with sea
side views.
Hull – Every year, 13 million tonnes of imported
cargo pass through the port which employs 5000
people. Fishing industry lands fish at Hull docks.
Holderness Country Park – provides tourists with a
large fishing lake and a dog walking area. Guests can
stay in either log cabins or caravans.
Easington Gas Terminal – provides 1000 jobs and
25% of UKs gas supply.
Humber Estuary: off-shore & on-shore wind turbines use
strong winds to generate renewable electricity.
Why have coastal areas developed?
Human Activities
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Improved Transport
Rising living standards
Range of jobs (e.g. Eastington for industry,
Bridlington for tourism).
Tourism (scenery and wildlife) (e.g
Flamborough Head and Spurn Head)
Attractive place to live (e.g. Bridlington –
views of the sea)
Second homes/retirement (e.g.
Bridlington)
Economic Activities
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Improved Transport and Communication
Available space (e.g. Hull for development
of industry and housing)
Large workforce (e.g. Hull which employs
5000 people in its dockland)
Natural Resources (e.g. fish in Hull, gas in
North Sea piped to Easington)
Tourism (e.g. Hornsea, Bridlington, Various
caravan and camping sites along the
coastline)
How is development affecting the environment?
Some animals and
birds have choked
on litter on beaches
from tourists.
Conflicts of Interest :
Different coastal users who
make problems for each
other.
Industrial units and
factories have polluted the
sea causing death of
aquatic life and thus
disrupting food chains.
Diesel/oil spillage
from the tankers may
affect marine life;
noise from tankers
Coral reefs (e.g. St Lucia)
are being damaged from
tourists collecting souvenirs
and anchors from fishing
vessels.
How is development
along the coast
damaging the local
environment?
•Oil refineries of S. Humber
pollute water for local
fishermen.
•Ships coming up R. Humber
cause danger for tourist
wind-surfers & jet skiers
•Wind turbines at Easington
can kill migrating birds using
Spurn for migration.
Footpath erosion at
Flamborough Head due
to high tourist numbers.
Cliff top developments
have made the cliffs
unstable which has
increased rates of erosion.
Sea defences along the Holderness
Coastline have stopped the
movement of sediment to Spurn
Head, an important habitat for
numerous rare birds .
How can we protect the coastline?
Protection Scheme
How does it protect the coastline?
Heritage Coast at
Flamborough Head
-Encourages the use of public transport which reduces cars, congestion, noise and
air pollution
- farmers receive extra money through grants if they farm in a way that protects
the environment and wildlife biodiversity (range of species)
- footpath erosion is reduced by encouraging people to stay on paths through
signage
Yorkshire Wildlife
Trust at Spurn and
Flamborough Head
-Organises seasonal beach cleans at two locations. All rubbish is separated out and
recycled where possible which promotes sustainability
-Helps to prevent millions of marine animals, birds, turtles and fish dying each year
as a result of entanglement or eating litter floating around in the sea or beach.
-Keeps beaches tidy which encourages tourists back into the area.
Greenbelts around
Bridlington and
Hull
-they have prevented new houses and industries from being built land ideal for
farming land.
-fewer development on cliff-faces has reduced the pressure on cliffs making them
more resistant to erosion and weathering.
-stopped woodlands and hedges being removed allowing for ecosystems to
continue to flourish.
Marine
Conversation Sites
(MCS)
-The MCS has helped reduced overfishing to protect fish stock numbers from
further declining. In the future, it is hoped that fish populations will increase.
-The MCS also prevents sand dredging of the sea bed which can damage nesting
sites of many fish.
Constructive and Destructive Waves
What determines the strength of a wave?
Swash is the
movement of
water up the
beach
Backwash in
the movement
of water down a
beach
-
Strength of the wind
How long the wind has been blowing
The distance between the ocean the wave has
crossed (fetch)
Constructive Waves
Destructive Waves
Strong Swash, Weak Backwash
Weak Swash, Strong Backwash
Deposits rather than erode
Erodes rather than deposits
Low wave height (less than 1 metre)
High wave height (more than 1 metre)
Low wave frequency
High wave frequency.
Erosion and Weathering
Key Terms:
Erosion – the wearing away of rocks by the action of the sea and their removal
Weathering – the breaking up of rocks in situ by the action of the weather, chemicals and
biology.
Erosion
Attrition
Energy from breaking waves causes rocks and
pebbles to smash into each other They
eventually break down into smaller and
rounder pieces
Abrasion
Materials, like boulders, pebbles and sand are
hurled against the cliff by breaking waves.
This causes undercutting and the breaking up
of rocks.
Hydraulic Action
Water is thrown into cracks within the cliff
by breaking waves. Air inside the cracks is
squashed by the water and the pressure
inside increases
When the wave sinks back, the pressurised
air expands explosively. This causes the
rocks to shatter so the cracks slowly
become bigger and deeper.
Weathering
Wetting/drying
Constant wetting and drying causes
rocks to expand and contract, resulting
in surface cracks and weakening of the
rock.
Freeze thaw Weathering
Water gets into cracks in rocks and
expands as it freezes, putting pressure
on the surrounding rock.
Corrosion
Carbon Dioxide dissolves in rainwater,
producing acid rain. This reacts with
minerals inside certain rocks (e.g.
limestone), causing them to be
weakened and easily dissolved.
Erosion on Hard Coastlines
Hard Coastline: Headlands and Bays
1) Hard (e.g. chalk)
and soft rock (e.g.
boulder clay) are
at right angles to
the coastline.
4) As the headland
juts out to sea, it
receives the full
force of the waves
energy. This allows
the headland to be
eroded slowly over
time.
2) Soft rock is eroded
at a faster rate by
hydraulic action and
abrasion.
3) Over time, a bay is formed within the soft rock. The shape of the coastline reduces the
energy forming constructive waves. This allows beaches to form.
Hard Coastline: Cave, Arches and Stacks
Headland
4) Overtime, the
base of the stack is
eroded by abrasion
which then topples
over in a storm to
form a stump.
1) A cave is formed
when hydraulic
action widens the
joints in the rock
over time.
2) An arch is formed
when hydraulic action
and abrasion continue to
erode the backwall of a
cave all the way through
the headland.
3)A stack is formed when the roof of
the arch is weathered by freeze thaw
action. This weakens it causing to
collapse as a rock fall due to gravity.
Hard Coastline: Wave cut notch and wave cut platform
2) The top of the cliff is
weakened by freeze
thaw weathering.
1) Erosion from the
sea (i.e. abrasion
and hydraulic
action) start to
undercut the cliff
base.
.
4) Cliff collapses due to gravity
as a rockfall.
5) The cliff slowly retreats back
leaving a wave cut platform
behind.
3) This wave cut notch increases in size until the weight of the cliff
can no longer be supported.
Erosion on Hard Coastlines
ROCKFALLS
Process:
Freeze thaw weathering is when water
enters cracks between rocks and freezes.
This causes the water to expand which
puts pressure on the surrounding rocks.
Over time, it weakens the rock causing it
to break up. This causes rock to fall from
the cliff face due to gravity as a rockfall.
Landforms
A scree slope of fallen rock is formed at
the bottom of the cliff face.
Erosion on Soft Coastlines
SLUMPING
Process:
Slumping is a rapid movement of boulder clay that
occurs on a curved slip plane.
It happens when water percolates (soaks into) into
the boulder clay until it becomes saturated with
water making it heavy. The weight of the cliff above
it forces the rock down towards the sea as a mud
flow.
Landforms:
A step like cliff face is present after the slumping has
occurred. Vegetation (originally from the cliff top)
will also be present in patches on the cliff face.
LANDSLIDES
Process:
A landslide is a rapid movement of boulder clay that
occurs on a slip plane that is parallel to the cliff face.
It happens when erosion from the sea undercuts the
base of the cliff. This destabilises the cliff face
causing the clay to slide down the cliff as a
landslide.
Landforms:
An accumulation of sediment remains at the base of
the cliff which is known as a scree slope.
How are beaches formed?
Swash Aligned Beach
Waves approach the
coastline and then break in
parallel to the coastline
Swash and backwash
move sediment up and
down the beach.
Creates an even profile
along the shoreline
During storms, berms
(ridges of sediment can
form).
Drift Aligned Beaches (longshore drift)
3)Backwash moves the
material straight back
down the beach to the
sea.
2) Swash
moves the
material up
the beach at
an angle.
1) Prevailing wind
direction moves waves
onshore at an angle.
4) Material is picked up
again and moved back up
the beach as swash.
6)The sediment
moves in a zig-zag
motion along the
beach. Over time,
large amounts of
sediment are
moved along the
beach.
5) Backwash brings the
material back down the
beach again.
How are spits and bars formed?
e.g. Spurn Head,
Holderness Coastline
e.g. Slapton Ley,
Devon
How is a spit formed?
How is a bar formed?
1. Waves carrying material are blown in the
direction of the prevailing wind.
1. Waves carrying material are blown in the
direction of the prevailing wind.
2. Longshore drift moves material along the
coast.
2. Longshore drift moves material along the
coast.
3. Where the coastline changes direction,
material is deposited in water sheltered by
the headland.
3. Where the coastline changes direction,
material is deposited in water sheltered by
the headland.
4. The material builds upwards and outwards
to form a spit.
4. The material builds upwards and outwards
to form a spit.
5. A mud flat starts to develop in the
sheltered water behind the spit due to less
erosion.
5. The spit continues to grow across the bay
area and joins to the headland to form a
bar.
6. Secondary winds can cause the end of the
spit to curve forming a hooked end
6. A lagoon is formed behind the bar. Over
time, this is filled up with sediment to form
land.
7. The salt marsh develops on the mud flat in
the sheltered water.
Why are
decisions made
to manage
coastal areas?
Some areas are protected from
the effect of coastal processes.
Understand that not all areas can be/need to be
protected.
−− Consider the issues associated with the
planning, decision making and management of
shorelines.
There are different methods that
can be used to protect coastlines
from the effects of natural
processes.
Describe the concept of ‘hard’ and ‘soft’ coastal
engineering.
Use an example(s) to illustrate the methods and
issues associated with:
−− hard engineering – use of sea walls, rock
armour, gabions, tetrapods, cliff drainage,
groynes.
−− soft engineering – use of beach
nourishment, beach recycling, beach reprofiling Replenishing.
Explore the reasons why different methods of
coastal management may be appropriate in
different locations.
Environmental management
protects some areas.
How can the
management of
coastal areas
be increasingly
sustainable?
The sustainability of coastal
areas requires the whole of the
coastal zone to be managed
effectively.
• Explore the idea of Integrated Coastal Zone
Management (ICZM) by looking at one example
of a coastal area in relation to its economic and
environmental sustainability. Consider:
−− the pressures on the area
−− the strategies being used to reduce the
pressures and ensure the long-term
sustainability of the area.
Protecting coastal areas from the
increasing threat of rising sea
levels will require the
development of different
approaches
• Investigate one example of the use of
managed realignment (retreat).
−− Describe the methods used.
−− Explain how they operate to protect the
coastal area from flooding.
−− Evaluate the significance of the methods in
relation to the increasing risk of coastal
Flooding.
Coastal Management
There are 4 Management Options
for each section of coastline:
No Active Intervention (do
nothing – and let the coast erode)
Hold the line (intervene to keep
the coastline where it is at present)
Advance the Line (build defences
further out from the existing
coastline)
Managed realignment (develop
defences further inland and permit
some coastal flooding)
Some areas are in greater need of protection than others. For
example there are a variety of reasons specifically economic and
social (socio-economic) why seaside towns need to be protected.
They are places where people live and they are also places where
money can be made specifically through tourism. Towns such as
Bridlington, Hornsea and Mappleton are in greater need of prrtection
than the farmland inbetween, the Easington Gas Terminal also
needs protecting because it is so important in providing gas for the
UK. Locally it also provides jobs.
The whole of the Holderness coast is vulnerable to erosion as it is
made of soft rock. This means decisions are made about which bits
to hold the line and which areas will have to be allowed to erode
back.
The Shoreline Management Plan SMP does this for the UK.
The aim of the Shoreline Management Plan is to identify which
areas of coast require protection, and which don’t. By looking at
the coast as a whole (a system) planners can make sure that
any changes to one part of the coast – will affect other parts in
a planned way and not give surprise effects.
Hard Engineering
Controlled disruption of natural processes by using man-made structures
Advantages - Protects the base of cliffs, land and buildings against erosion. Can prevent
coastal flooding in some areas.
Disadvantages = Expensive to build. Curved sea walls reflect the energy of the waves
back to the sea. This means that the waves remain powerful. Over time the wall may
begin to erode. The cost of maintenance is high.
Advantages - Absorb the energy of waves. Allows the build up of a beach.
Disadvantages = Can be expensive to obtain and transport the boulders.
Advantages - Easily installed, cheaper than sea wall
Disadvantages - Not very attractive, needs frequent checking & repair, not easy for
people to get over to get to beach, may contain rats nests
Advantages = Prevents the movement of beach material along the coast by longshore drift.
Allows the build up of a beach. Beaches are a natural defence against erosion and an
attraction for tourists.
Disadvantages - Can be seen as unattractive. Costly to build and maintain.
Advantages - Easily installed. Cheaper, than sea wall, deflects wave power
Disadvantages - Can be eroded from below easily, needs frequent repair, not very
attractive
Revetment
Popular option in Japan – seen to be effective
Can be built on-site
Allows some waves through – so less ‘reflected’ wave damage
Tetrapods
Soft Engineering
Working with the natural processes of sea and sand in a more environmentally sustainable way. Using the
natural processes to bring about an intended effect.
Beach Re-Cycling
Advantages - Adds to tourist amenity by making bigger beach, attractive, works with the natural processes of
the coast
Disadvantages - Needs frequent renewal of more sand, does not protect cliff face from winter storm waves.
Beach Re-Building
Advantages - Adds to tourist amenity by making bigger beach, attractive, works with the natural processes of
the coast
Disadvantages - Needs frequent renewal of more sand, does not protect cliff face from winter storm waves.
Beach Replenishment
Sand and gravel is hoovered up by a dredger ship off the
coast, and sprayed onto the lower beach at high tide.
At low tide, bulldozers push the material up the beach to raise
the height of the beach
This takes place 3 times a year – in early Autumn after the
holiday season, in January before the main winter storms, and
at Easter just before the holiday season and to correct winter
storm damage to the beach.
Reasons behind the Beach Replenishment scheme at Pevensey
Reason 1 : Almost all of the 150 wooden Groynes had deteriorated and either needed repair or replacement.
Both would be very expensive and use a lot of hardwood – which isn’t a sustainable solution. They were
removed in 2007.
Reason 2 : The beach environment has many valuable plant species and these needed to be protected and
encouraged to thrive.
Reason 3 : There are many coastal homes looking out over the beach – and their protection, but also their
views needed preserving.
Re-profiling
Beach Re-profiling
This means changing the gradient of the beach to
the best one for absorbing the wave energy.
Winter storms remove lots of the lower beach with
their strong backwash.
Bulldozers spread the sand evenly across the
beach in Spring to create a more even profile –
which is better at absorbing wave energy.
Sea Level Rise, Global Warming and Managed Retreat
Climate change is putting increasing pressure on coastal defences as sea levels rise and are predicted to rise
further into the future (Holderness = 50cm rise predicted in 50 years)
Management options for protecting coasts from rising sea levels consist of :
Do nothing – let the sea flood onto land
Move entire communities inland onto higher land
Build higher defences with sea walls & embankments
Plan for Managed Retreat (coastal realignment) 'THIS IS SEEN AS THE PREFERED OPTION
The Humber faces increasing problems from rising sea levels.
The existing defences are already starting to become inadequate was breached by a storm surge in 2003.
The engineers had to decide whether to repair the breach, or put in a longer term solution.
Sea level rises along the Humber estuary are forecast to continue over the next century
Managed realignment involves the construction of new sea walls at a location behind existing sea walls to
create parcels of land that can be flooded to create new inter-tidal environments.
Wallasea Island, Essex
Location:
Wallasea Island is a low-lying coastal island
formed at the confluence of the Rivers Crouch
and Roach in Essex.
What has happened?
With the coastal defences in the north of the
island crumbling away, the government
decided to realign (change the shape of) the
northern part of the island by constructing a
new embankment (wall) inland (further south)
and allow the sea to further break through
(breach) the old sea defences.
Benefits:
 The new mudflats and salt marsh (created where the defences are breached – see photo) will help
protect the new sea wall
 They will offer additional protection to the property to the south
 The scheme aims (still too early to assess) to bring back bird habitats which were lost to previous
development, improve flood defences on the island and create new leisure opportunities
Costs:
 The scheme cost taxpayers £7.5 million
 Sediment (mud) and vegetation (salt marsh) has not been immediate