The Coastal Zone Notes With Case studies

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  • Created on: 18-04-14 14:11
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Coastal Management
Coastal Weathering and erosion
Mechanical: the breakdown of rocks without changing its chemical composition.
It happens when the temperature alternates above and below 0°C (the freezing point of
Water gets into the cracks of the rock.
When the water freezes it expands, which puts pressure onto the rock.
When the water thaws it contracts, which releases the pressure in the rock.
Repeated freezing and thawing widens the cracks and causes the rock to break up.
Chemical: when weak acids for example rain dissolves the rocks.
Rainwater has carbon dioxide in it, which makes it a weak carbonic acid.
Carbonic acid reacts with rock that contains calcium carbonate, e.g. Carboniferous
limestone, so the rocks are dissolved by the rainwater.
Mass Movement
Mass movement is when material shifts down a slope as one
Mass movement is the shifting of rocks and loose material down a slope e.g. a cliff. It
happens when the force of gravity acting on a slope is greater than the force supporting it.
Mass movement cause coasts to retreat rapidly.
They're more likely to happen when the material is full of water.
On the top is a layer of sandy gravel and beneath is a layer of
clay. The sandy gravel is permeable so the water seeps
through it however the clay is impermeable and holds water
from the sand above and the rain falling directly on it. Soon the
clag turns into a soggy slippery mess then helped by the
waves it happens and it material shifts down with a rotation
this is called rotational cliff slumping.
Coastal Erosion:
Waves Wear Away the coast using four processes of Erosion
Hydraulic power: waves crash against rock and compress the air in the cracks. This puts pressure on
the rock. Repeated compression widens the cracks and makes bits of rock break off.
Abrasion: eroded particles in the water scrape and rub against rock removing small pieces.
Attrition: eroded particles in the water smash into each other and break into smaller fragments.
Their edges also get rounded off as they rub together.

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Solution: weak carbonic acid in seawater dissolves rock like chalk and limestone.
Types of waves:
The waves that carry out erosional processes are
1) Destructive waves have a high frequency
(10-14 waves per minute)
2) They're high and steep
3) Their backwash (the movement of the water
back down the beach) is MORE POWERFUL
than their swash (the movement of the water
up the beach). This means material is removed from the coast by LONGSHORE DRIFT.…read more

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Headlands and bays form where there are alternating bands of resistant and less
resistant rock along a coast.
3) The less resistant rock (e.g. clay) is eroded quickly and forms a bay- Bays have a gentle
4) The resistant rock (e.g. chalk) is eroded more slowly and it's left jutting out, forming a
headland- headlands have steep sides.
Headlands are eroded to form Caves, Arches and Stacks
1) Headlands are usually made of resistant rocks
that have weaknesses like cracks.…read more

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Traction- large particles like boulders are pushed along the sea bed by the force of the
Suspension- small particles like silt and clay are carried along in the water
Saltation- pebble sized particles are bounced along the sea bed by the force of the water.
Solution- soluble materials dissolve in the water and are carried along.
Deposition is the dropping of material
1) Deposition is when material being carried by the sea water is dropped on the coast.…read more

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Spits are just beaches that stick out into the sea- they're joined to the coast at one end. If a spit
sticks out so far that it connects with another bit of the mainland, it'll form a bar. Spits and bars
are formed by the process of longshore drift.
1) Spits form at sharp bends in the coastline
e.g. at a river mouth.
2) Longshore drift transports sand and
shingle past the bend and deposits it in
the sea.…read more

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The Sea Level is Rising due to Global Warming
The global sea level is rising at about 2mm per year. This might not sound like a lot, but sea level has
increased by about 20cm in the past century. It's predicted to rise about 18-59cm by 2100. The
cause of this is global warming- the rapid rise in global temperatures over the last 100 years.…read more

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The government has to make policies to reduce the impacts of future flooding. They can do things
like building more or better flood defences or they can manage the use of areas that might be
flooded e.g. by stopping people living there.
The average rate of erosion at Holderness is about 1.8 metres per year.
Main reasons for the rapid erosion
1) Easily eroded rock type- the cliffs are
mostly made of boulder clay which is easily
eroded.…read more

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There's a sea wall, wooden groynes and rock armour at Hornsea that protect the village
from erosion and flooding.
5) Bridlington is protected from erosion and flooding by a 4.7km long sea wall as well as
wooden groynes.
The strategies are locally successful but cause problems elsewhere
1) Groynes protect local areas but cause narrow beaches to form further down the
Holderness coast. This increases erosion down the coats e.g. Cowden farm (south of
Mappleton) is now at risk of falling into the sea.…read more

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Environmental - Habitats were flooded and contaminated- wildlife that couldn't move out of
reach of the floodwater was in danger.
Political impacts- Bangladesh is very poor and they cannot afford to prepare properly for flood
disaster. Some areas have raised flood shelters but there are not enough. Difficult decisions
need to be made how to protect areas, provide early warning systems and emergency aid.…read more

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Snakes and lizards have thick, scaly skin to reduce water loss from their bodies. It also
protects them from rough undergrowth on the Heathland.
Facts needed for formation
A plentiful supply of sand
Strong winds to transport sand particles through Saltation (bouncing)
An obstacle to trap sand e.g. a plant. Plants are therefore central to the formation,
growth and character of sand dunes.…read more


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