GEOGRAPHY REVISION – PHYSICAL
UNIT ONE: Coastal Systems and Landscapes
Coast: The dynamic interface where sea and land meet
Systems approach: States the components in a landscape, their relationship to each other & their place within a
system (E.g. INPUTS ---- PROCESSES ---- OUTPUTS). This system helps explain changes & help predict possible
consequences or human impact. There interaction aids the understanding as to why some are rapidly changing and
some are not.
Main System elements:
Inputs: material or energy moving into the system from outside - introductions of sediment and energy (wind,
waves)
Outputs: material or energy moving from the system to outside - Sediment and energy losses to the system
Stores: Where material is held within a system – The individual elements or parts of a system
Flows: Transfers of energy and sediment from one location to another – The links or relationships between the
components
Energy: Something which powers a system – (Sun)
Positive Feedback – Where a flow/transfer leads to increase or growth (groynes trap sediment, depriving other
areas, exacerbating erosion)
Negative Feedback – Where a flow/transfer leads to decrease or decline
A coastal system is open – it receives inputs from elsewhere, and outputs sediment and energy.
Dynamic Equilibrium: A balance between inputs and outputs in a system.(relative stability usually)
If one becomes imbalanced or an external factor acts on the system, the equilibrium is disturbed.
Processes affecting coasts
Marine: waves, tides, currents, LSD
Terrestrial: rock type, structure, sub-aerial
Atmospheric: weather, climate, moon
Biological: chemical reactions
Fluvial – Rivers/Deltas
Tectonic – Earthquakes
Human – Tourism, recreation, ports, settlement, global warming
Landform: A distinctive feature (of a coat) e.g. Just a Stack
Landscape: A place/area which obtains multiple landforms e.g. a headland and a stack
Coastal systems do not operate in isolation. They are interlinked – both affected and being affected by change.
(This connection can be seen in the natural and human-induced climate change)
For example, when sea levels rose during the quaternary and interglacial periods in response to changes in the global
water cycle. And now recent changes in global carbon cycles are causing a sea level rise from global warming.
, COASTAL ZONES
Between HWM &
Betwee Between LWM Area beyond
where marine and where waves influence of sea on
n HWM
activity ends no longer impact the landscape
& LWM
landscape
Scales & cells
Coastal systems can be seen operating at various scales - An individual beach may be considered a material store –
and subject to inputs and outputs.
Sources of Sediment:
- Rivers - Cliff Erosion
- LSD - Wind
- Glaciers - Offshore
Sediment budget: Amount of sediment coming in and out of a system/area.
If inputs exceed outputs (surplus), it will give a positive sediment budget (Beach will extend seawards)
If outputs exceed inputs (deficit), it will give a negative sediment budget (Beach becomes smaller - inwards)
Equal amounts, it will give a balanced or neutral sediment budget (Beach remains the same)
This state becomes one of dynamic equilibrium as material may still be added & removed but within a net balance
Major components of sediment budget:
Sources (new sediment), Sinks (lost from the beach), Transport (moved to different parts)
At a larger scale, systems operate on more extensive sections of coastline.
Sediment (Littoral) cells: A stretch of coastline with self-contained cycles of erosion, transportation & deposition
- These tend to be many kilometres in length, bounded by headlands at either end
- They represent recycled sections of coast, maintaining a relative balance
Closed sediment systems: A coastal system that receives no additional sediment inputs and has no losses of
sediment to areas external to the system.
These cells can also have smaller ‘sub cells’ BUT 11 distinctive littoral cells around England & it is the disruption
of these cells as to why we encounter problems with erosion.
This erosion will occur when waves and currents remove sediment faster than it can be replaced
SMALL DEFICITS, LARGE BEACH = small impact, SMALL DEFICITS, SMALL BEACH = Big impact
If a key energy input changes, the system alters in response transporting the sediment around within the system.
(particular sediment stores may change in volume, as material is removed from one area and deposited elsewhere)
Sources of energy at the coast
The sun and wind – create the energy behind waves
Primary source of energy for all natural systems is the sun – heat and light is converted by natural processes (e.g.
photosynthesis) to form energy.
At the coast, main form of energy is derived from the sea in the form waves – which are mostly formed by wind.
UNIT ONE: Coastal Systems and Landscapes
Coast: The dynamic interface where sea and land meet
Systems approach: States the components in a landscape, their relationship to each other & their place within a
system (E.g. INPUTS ---- PROCESSES ---- OUTPUTS). This system helps explain changes & help predict possible
consequences or human impact. There interaction aids the understanding as to why some are rapidly changing and
some are not.
Main System elements:
Inputs: material or energy moving into the system from outside - introductions of sediment and energy (wind,
waves)
Outputs: material or energy moving from the system to outside - Sediment and energy losses to the system
Stores: Where material is held within a system – The individual elements or parts of a system
Flows: Transfers of energy and sediment from one location to another – The links or relationships between the
components
Energy: Something which powers a system – (Sun)
Positive Feedback – Where a flow/transfer leads to increase or growth (groynes trap sediment, depriving other
areas, exacerbating erosion)
Negative Feedback – Where a flow/transfer leads to decrease or decline
A coastal system is open – it receives inputs from elsewhere, and outputs sediment and energy.
Dynamic Equilibrium: A balance between inputs and outputs in a system.(relative stability usually)
If one becomes imbalanced or an external factor acts on the system, the equilibrium is disturbed.
Processes affecting coasts
Marine: waves, tides, currents, LSD
Terrestrial: rock type, structure, sub-aerial
Atmospheric: weather, climate, moon
Biological: chemical reactions
Fluvial – Rivers/Deltas
Tectonic – Earthquakes
Human – Tourism, recreation, ports, settlement, global warming
Landform: A distinctive feature (of a coat) e.g. Just a Stack
Landscape: A place/area which obtains multiple landforms e.g. a headland and a stack
Coastal systems do not operate in isolation. They are interlinked – both affected and being affected by change.
(This connection can be seen in the natural and human-induced climate change)
For example, when sea levels rose during the quaternary and interglacial periods in response to changes in the global
water cycle. And now recent changes in global carbon cycles are causing a sea level rise from global warming.
, COASTAL ZONES
Between HWM &
Betwee Between LWM Area beyond
where marine and where waves influence of sea on
n HWM
activity ends no longer impact the landscape
& LWM
landscape
Scales & cells
Coastal systems can be seen operating at various scales - An individual beach may be considered a material store –
and subject to inputs and outputs.
Sources of Sediment:
- Rivers - Cliff Erosion
- LSD - Wind
- Glaciers - Offshore
Sediment budget: Amount of sediment coming in and out of a system/area.
If inputs exceed outputs (surplus), it will give a positive sediment budget (Beach will extend seawards)
If outputs exceed inputs (deficit), it will give a negative sediment budget (Beach becomes smaller - inwards)
Equal amounts, it will give a balanced or neutral sediment budget (Beach remains the same)
This state becomes one of dynamic equilibrium as material may still be added & removed but within a net balance
Major components of sediment budget:
Sources (new sediment), Sinks (lost from the beach), Transport (moved to different parts)
At a larger scale, systems operate on more extensive sections of coastline.
Sediment (Littoral) cells: A stretch of coastline with self-contained cycles of erosion, transportation & deposition
- These tend to be many kilometres in length, bounded by headlands at either end
- They represent recycled sections of coast, maintaining a relative balance
Closed sediment systems: A coastal system that receives no additional sediment inputs and has no losses of
sediment to areas external to the system.
These cells can also have smaller ‘sub cells’ BUT 11 distinctive littoral cells around England & it is the disruption
of these cells as to why we encounter problems with erosion.
This erosion will occur when waves and currents remove sediment faster than it can be replaced
SMALL DEFICITS, LARGE BEACH = small impact, SMALL DEFICITS, SMALL BEACH = Big impact
If a key energy input changes, the system alters in response transporting the sediment around within the system.
(particular sediment stores may change in volume, as material is removed from one area and deposited elsewhere)
Sources of energy at the coast
The sun and wind – create the energy behind waves
Primary source of energy for all natural systems is the sun – heat and light is converted by natural processes (e.g.
photosynthesis) to form energy.
At the coast, main form of energy is derived from the sea in the form waves – which are mostly formed by wind.
