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Summary AQA Physical geography- Coasts 4 MARKERS
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AQA Physical geography complete 4 marker practice questions for the A-Level.
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UNIT CRITERIACoasts as natural systems
Systems in physical geography: systems concepts and their application to the development of coastal
landscapes – inputs, outputs, energy, stores/components, flows/transfers, positive/negative feedback,
dynamic equilibrium
The concepts of landform and landscape and how related landforms combine to form characteristic
landscapes.
Systems and processes
Sources of energy in coastal environments: winds, waves (constructive and destructive), currents and
tides.
Low energy
Sediment sources, cells and budgets.
Geomorphological processes: weathering, mass movement, erosion, transportation, and deposition.
Coastal landscape development
Origin and development of landforms and landscapes of coastal deposition.
Estuarine mudflat/saltmarsh environments and associated landscapes; factors and processes in their
development.
Coastlines of emergence and submergence
Origin and development of associated landforms: fjords
Recent and predicted climatic change and potential impact on coasts.
Coastal management and human intervention in coastal landscapes.
Traditional approaches to coastal flood and erosion risk: hard and soft engineering.
Sustainable approaches to coastal flood risk and coastal erosion management: shoreline
management/integrated coastal zone management.
Case studies
Sundarbans - a contrasting coastal landscape beyond the UK to illustrate and analyse how it presents
risks and opportunities for human occupation and development and evaluate human responses of
resilience, mitigation and adaptation
4-mark questions:
Coasts as natural systems
Outline the role of dynamic equilibrium in coastal landscapes
A system is in the state of dynamic equilibrium when the inputs and outputs are balanced, this
means that the stores stay the same. However, if the inputs increase and the outputs stay the
same, the state of equilibrium is upset. Coastal landscapes are a result of continuous change and
when the dynamic equilibrium is unbalanced, positive and feedback loops become important in the
development of the coastline. A negative feedback loop attempts to nullify the change that
originally took place and moves the system back to dynamic equilibrium. A positive feedback loop
however, exacerbates the original change that took place and can send the system further away
from dynamic equilibrium.
Explain the concept of feedback loops in relation to coastal landscapes
A system is an assemblage of interrelated parts that work together by way of some driving
process, they have a series of stores and components and have flows or connections. Coasts are
dynamically changing environments and feedback loops are essential in their development. When
a system is moved away from dynamic equilibrium and the change is reversed to its original state,
nullifying the change, this is evidence of negative feedback. However, when a change takes place
and the system is further moved away from dynamic equilibrium, exacerbating the change, this is
evidence of positive feedback.
, Explain the concept of positive feedback loops in relation to coastal landscapes
A positive feedback loop in relation to a system within a coastal landscape, exacerbates an
original change that has taken place. Positive feedback moves a system further away from its
original state of dynamic equilibrium.
Example- A storm causes more erosion then usual ->The ridge of a sand dune is breached-> The
ridge is then undercut by wind erosion -> This breaks up the dune making it more likely to be
eroded
Explain the concept of negative feedback loops in relation to coastal landscapes
A negative feedback in relation to a coastal system nullifies the original change that took place.
Negative feedback sends the system back to a state of dynamic equilibrium and opposes the
original change, where the inputs and outputs become balanced.
An example of a negative feedback loop in a coastal system- sediment is eroded from the beach
during a storm -> Sediment is deposited offshore forming an offshore bar -> Waves now break
before reaching the beach, dissipating their energy and reducing further erosion when they reach
the beach -> When the storm calms normal wave conditions rework sediments from the offshore
bar back to the beach -> The beach is in dynamic equilibrium
Systems and processes
Deduce the differences between constructive and destructive wave formation
Constructive and destructive waves operate on coastal landscapes and have very different
characteristics. Destructive are characterised by a dominant backwash, high energy coastlines
and short wave lengths and periods. Destructive waves also occur at a high frequency of around
10-14 per minute. They erode the beach, making a beach with a steep profile. Constructive waves
are characterised by a dominant swash, pushing material up the beach. They have a low
frequency of around 6-8 waves per minute and are often found in low energy environments.
Constructive waves create wide beach profiles with a gentle slope.
Outline the role of waves in changing coastal landscapes
Waves are a dominant process in determining the coastal landscape and its associated landforms.
They are influenced by wave energy and play the most important role in coastal formation. There
are two types of waves; destructive and constructive waves. Constructive waves build up the
beach whereas destructive waves break down the beach and erode material. Destructive waves
often create a beach with a steep profile, constructive waves however create a beach with a gentle
profile. Waves also significantly determine the characteristics of changing coastal landscapes. A
coastline with destructive waves will often contain features like caves, arches, stacks and stumps
whereas a coastline associated with constructive waves will have features such as long, wide
beaches.
Outline the role of wind in changing coastal landscapes
Wind is an important feature in the changing coastal landscapes and can determine the wave
energy that approaches the coastline. Wind is a vital input in the coast system and is a primary
source of energy for other processes, but it is also an important agent of erosion and transport
itself. Where wind speeds are high and uninterrupted, wave energy will tend to be stronger. Wind
also plays a vital role in wave formation, the energy acquired by waves is determined by the length
of time the wind has been blowing over its fetch. Generally, longer fetches are accompanied with
stronger, more destructive waves.
Outline the role of tides in changing coastal landscapes
Tides are the periodical rise and fall of the sea due to the gravitational pull of the sun and moon.
The moon pulls water towards it, creating a high tide and a bulge on the opposite side of the earth.
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