Coastal systems and landscapes
Coasts as natural systems
The coast as an open system
It has inputs that originate from outside the system + outputs to other
natural systems.
As an open system, the coast has important links with other natural
systems e.g. the atmosphere (wind), tectonics + ecosystems. These systems
are linked together by flows of energy + the transfer of material.
The coastal system
There are 11 sediment cells in England and Wales, forming the basis for
coastal management. There are clear inputs, transfers, stores + outputs of
sediment.
,Systems term Definition Coastal example
Input Material or energy Precipitation, wind
moving into a system
from outside
Output Material or energy Ocean currents, rip
moving from the system tides, sediment transfer,
to the outside evaporation
Energy Power or driving force Energy associated with
flowing water, the
effects of gravity on
cliffs and moving air
(wind energy
transferred to wave
energy)
Stores/components The individual elements Beach, sand dunes,
or parts of a system nearshore sediment
Flows/transfers The links or Wind-blown sand, mass
relationships between movement processes,
the components longshore drift
, cliffs and moving air
(wind energy
transferred to wave
energy)
Stores/components The individual elements Beach, sand dunes,
or parts of a system nearshore sediment
Flows/transfers The links or Wind-blown sand, mass
relationships between movement processes,
the components longshore drift
Positive feedback Where a flow/transfer Coastal management
leads to a increase or can inadvertently lead
growth to an increase in erosion
elsewhere along the
coast. Groynes trap
sediment, depriving
areas further down drift
of beach replenishment
and this can exacerbate
erosion. Sea walls can
have the same effect by
transferring high energy
waves elsewhere along
the coast.
Negative feedback Where a flow/transfer When the rate of
leads to a decrease or weathering and mass
decline movement exceeds the
rate of cliff-foot erosion
a scree slope is formed.
Over time, this apron of
material extends up a
cliff face protecting the
cliff from subaerial
processes. This leads to
a reduction in the
effectiveness of
weathering and mass
movement.
Dynamic equilibrium This represents a state Constructive waves
of balance within a build up a beach,
constantly changing making it steeper. This
system encourages the
formation of destructive
waves that plunge
rather than surge.
Redistribution of
sediment offshore by
destructive waves
reduces the beach
gradient which, in turn,
encourages the waves
to become more
constructive. This is a
state of constant
, a reduction in the
effectiveness of
weathering and mass
movement.
Dynamic equilibrium This represents a state Constructive waves
of balance within a build up a beach,
constantly changing making it steeper. This
system encourages the
formation of destructive
waves that plunge
rather than surge.
Redistribution of
sediment offshore by
destructive waves
reduces the beach
gradient which, in turn,
encourages the waves
to become more
constructive. This is a
state of constant
dynamic equilibrium
between the type of the
wave and the angle of
the beach.
Links between the coastal system and other natural systems
Coastal systems don’t operate in isolation - interlinked with physical and
human systems e.g. climate change.
During Quaternary periods, sea levels rose and fell several times. Affecting
the location + types of landforms. Rising sea levels are affecting
ecosystems.
Coasts as natural systems
The coast as an open system
It has inputs that originate from outside the system + outputs to other
natural systems.
As an open system, the coast has important links with other natural
systems e.g. the atmosphere (wind), tectonics + ecosystems. These systems
are linked together by flows of energy + the transfer of material.
The coastal system
There are 11 sediment cells in England and Wales, forming the basis for
coastal management. There are clear inputs, transfers, stores + outputs of
sediment.
,Systems term Definition Coastal example
Input Material or energy Precipitation, wind
moving into a system
from outside
Output Material or energy Ocean currents, rip
moving from the system tides, sediment transfer,
to the outside evaporation
Energy Power or driving force Energy associated with
flowing water, the
effects of gravity on
cliffs and moving air
(wind energy
transferred to wave
energy)
Stores/components The individual elements Beach, sand dunes,
or parts of a system nearshore sediment
Flows/transfers The links or Wind-blown sand, mass
relationships between movement processes,
the components longshore drift
, cliffs and moving air
(wind energy
transferred to wave
energy)
Stores/components The individual elements Beach, sand dunes,
or parts of a system nearshore sediment
Flows/transfers The links or Wind-blown sand, mass
relationships between movement processes,
the components longshore drift
Positive feedback Where a flow/transfer Coastal management
leads to a increase or can inadvertently lead
growth to an increase in erosion
elsewhere along the
coast. Groynes trap
sediment, depriving
areas further down drift
of beach replenishment
and this can exacerbate
erosion. Sea walls can
have the same effect by
transferring high energy
waves elsewhere along
the coast.
Negative feedback Where a flow/transfer When the rate of
leads to a decrease or weathering and mass
decline movement exceeds the
rate of cliff-foot erosion
a scree slope is formed.
Over time, this apron of
material extends up a
cliff face protecting the
cliff from subaerial
processes. This leads to
a reduction in the
effectiveness of
weathering and mass
movement.
Dynamic equilibrium This represents a state Constructive waves
of balance within a build up a beach,
constantly changing making it steeper. This
system encourages the
formation of destructive
waves that plunge
rather than surge.
Redistribution of
sediment offshore by
destructive waves
reduces the beach
gradient which, in turn,
encourages the waves
to become more
constructive. This is a
state of constant
, a reduction in the
effectiveness of
weathering and mass
movement.
Dynamic equilibrium This represents a state Constructive waves
of balance within a build up a beach,
constantly changing making it steeper. This
system encourages the
formation of destructive
waves that plunge
rather than surge.
Redistribution of
sediment offshore by
destructive waves
reduces the beach
gradient which, in turn,
encourages the waves
to become more
constructive. This is a
state of constant
dynamic equilibrium
between the type of the
wave and the angle of
the beach.
Links between the coastal system and other natural systems
Coastal systems don’t operate in isolation - interlinked with physical and
human systems e.g. climate change.
During Quaternary periods, sea levels rose and fell several times. Affecting
the location + types of landforms. Rising sea levels are affecting
ecosystems.
