AQA gcse geography coast notes

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  • Created by: Katie789
  • Created on: 21-03-13 14:07
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Waves ­ how formed, how do they affect the coast
Waves are caused by friction between the wind and water causing the water to swell.
The size and energy of a wave is influenced by:
how long the wind has been blowing
the strength of the wind
how far the wave has travelled (the fetch)
Types of wave (constructive and destructive) ­ diagrams, processes
Destructive waves are created in storm
conditions.
They are created from big, strong waves
when the wind is powerful and has been blowing
for a long time.
They occur when wave energy is high and
the wave has travelled over a long fetch.
They tend to erode the coast.
They have a stronger backwash than swash.
They have a short wave length and are high and steep.
Constructive waves
They are created in calm weather and are
less powerful than destructive waves.
They break on the shore and deposit
material, building up beaches.
They have a swash that is stronger than the
backwash.
They have a long wavelength, and are low
in height.

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Coastal Processes ­ weathering:
when rocks and surface materials are broken down through the actions of the atmosphere we call it
weathering. weathering weakens rocks at the coast and makes them more likely to be affected by
mass movement and erosion
Chemical: when weak acids for example rain dissolves the rocks.
Physical : due to temperature, frost, water etc. freeze thaw weathering is when the
constant freezing of water and then melting again causes cracks in the rocks.…read more

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Solution: Minerals are dissolved in sea water and carried in solution. The load is not visible. Load can
come from cliffs made from chalk or limestone, and calcium carbonate is carried along in solution.
Longshore Drift :
The continual swash and backwash that carries material along the coast is called longshore drift.
Coastal deposition:
When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying. This is
called deposition.…read more

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The process repeats and the cliff continues to retreat
Wave cut platforms.
Wave cut platforms are the platforms at the bottom of a wave cut platform, formed during cliff
erosion.
Caves, arches and stacks
Hydraulic action is the principle process taking place here. The water works is way in through a crack
in the cliff, and over a period of time a cave is formed. When the cave breaks through to the other
side it becomes an arch.…read more

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These plants trap more sediment and contribute organic matter when they die. These
processes help the salty marsh to grow.
6. Eventually the salt marsh will grow further and an even more complex set of plants will
colonise the area, until the climax community of alder and ash trees is reached, with a fully
developed creek system. This is known as vegetation SUCCESSION.
Threats.…read more

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Case Study: Coastal Flooding
Bangladesh (LEDC):
Bangladesh is an LEDC. The land is
densely populated. Most of the land
forms a delta from three main rivers
- Ganges, Brahmaputra and
Meghna.
Twenty-five per cent of Bangladesh
is less than 1 metre above sea level.
Flooding is an annual event as the
rivers burst their banks.
Advantages to living in Bangladesh
The flat floodplains of the delta are very fertile.
Rice is grown.
Disadvantages to living in Bangladesh
The low-lying islands are very vulnerable.…read more

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Schools, hospitals and trains destroyed
Rising sea level ­ causes and consequences of sea level rise.
The sea level is rising due to global warming causing the polar ice caps to melt. This means there is
more water, which would mean sea levels could rise significantly.
Many parts of England would become flooded, especially the south west including London. Before
that the Thames barrier would be put under increasing pressure and may not be enough to withstand
tidal surges.…read more

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Disadvantages
Can be expensive to obtain and transport
the boulders.
Soft engineering (Beach nourishment, Dune regeneration, Marsh creation, Managed retreat)
Beach management
This replaces beach or cliff material that has been removed by erosion or longshore drift.
The main advantage is that beaches are a natural defence against erosion and coastal flooding.
Beaches also attract tourists.
It is a relatively inexpensive option but requires constant maintenance to replace the beach material
as it is washed away.…read more

Comments

Harvi.l

very helpful

N.Smith

awesome

Mr A Gibson

These are great for AQA or any other awarding body because they cover all the main points that you will find in the specification relating to coasts. There are some good examples too and also the diagrams used are clear and accurate. A great addition to your revision resources.

tobinoc

  1. have you ever been to Hawkshead
Xxx_J4Y-M3-ph1lIPs0N_xxX

8/8 it was gr8

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