Coastal systems and landscapes
- System- A process/collection of processes that transform inputs into outputs.
- The coast is an Open system since its inputs come from outside the system e.g.
sediment from rivers and it's outputs are transferred away from the coast and
into other natural systems e.g. atmosphere.
Positive feedback- When a flow/transfer leads to an increase or growth further
away from dynamic equilibrium e.g. when coastal management strategies like
groynes lead to an increase in erosion elsewhere.
Positive feedback- when a flow/transfer leads to a decrease/decline which moves
towards dynamic equilibrium
Dynamic equilibrium- A state of balance within a constantly changing system
Inputs- Something {material/ energy} that enters the system
Examples of energy inputs at the coast
Waves Salt spray
Wind, tides
Examples of material inputs at the coast
Products of erosion Weathering processes
Deposition
What are stores/sinks and give some examples at the coast?
Stores/sinks of sediment and material like:
Beaches Cliffs.
Sand dunes Wave cut platforms + notches
Spits Stumps + stacks
Bars Salt marshes
Tombolos Tidal flats
Headlands Offshore bands + bars
Bays
What are transfers/ flows and give some examples at the coast?
Processes that link the inputs, outputs + stores like:
, Mass movement Transportation
Longshore drift Wind blowing sand
Weathering Deposition
Erosion
What is an output? Give some coastal examples
Something that leaves the system like:
Ocean currents Water via evaporation
Rip tides Sediment transfers
Give some examples of sediment sources + why they are sources at the coast
Rivers- sediment transported by them
Cliff erosion- Eroded material from there
Wind- In glacial/ hot environments =wind blown sand = deposited in coastal
regions {this can lead to sand dunes}
Glaciers- if chunks of ice break off glaciers/ice sheets, they can deposit the
sediment trapped in them in the sea
Offshore sediment- sediment from offshore can be transported into the
coastal zone by waves, tides and currents
Longshore drift- from one stretch of coastline to another, as an output to an
input
Explain the formation of a wave- Wind blows over the sea surface, transfers
energy to it via frictional drag, and this forms a wave
What are the factors that affect waves?
Strength of the wind
The length of time it's blowing for
Fetch {The stretch of ocean water over which the wind blows}
Give the characteristics of a constructive wave
Flat
Low wave height
Long wavelength
, Strong swash that carries and deposits material up the beach
Low frequency {6-8 waves / minute}
Creates gently sloping beaches + a weak backwash
Give the characteristics of a destructive wave
Large wave height Weak backwash
Short wavelength Creates steep beaches
Steep wave front Strong swash that erodes beach
material + cliffs
High frequency {13-15 waves/
minute}
Describe wave refraction
The process by which waves turn + lose energy around a headland on uneven
coastlines. The wave energy is focused at the headlands, since, as the waves come
in they are high energy, and the water around headlands is shallow so they
become steep, high + short, and the part of the wave that's in deeper water moves
forward faster, causing the wave to bend or refract, being concentrated at the
headland, so it also concentrates the erosion on the headland too, which is
negative feedback
What are tides?
Changes in the level of seas/oceans caused by the gravitational pull of the moon
{energy source}. The UK experience 2 high + 2 low tides each day.
What is tidal range?
The difference between the high + low tide
What is a spring tide?
When the moon is in line with the sun and the Earth {full/new moon} =
strong gravitational pull = higher high tides + lower low tides = larger tidal
range
What is a neap tide?
- System- A process/collection of processes that transform inputs into outputs.
- The coast is an Open system since its inputs come from outside the system e.g.
sediment from rivers and it's outputs are transferred away from the coast and
into other natural systems e.g. atmosphere.
Positive feedback- When a flow/transfer leads to an increase or growth further
away from dynamic equilibrium e.g. when coastal management strategies like
groynes lead to an increase in erosion elsewhere.
Positive feedback- when a flow/transfer leads to a decrease/decline which moves
towards dynamic equilibrium
Dynamic equilibrium- A state of balance within a constantly changing system
Inputs- Something {material/ energy} that enters the system
Examples of energy inputs at the coast
Waves Salt spray
Wind, tides
Examples of material inputs at the coast
Products of erosion Weathering processes
Deposition
What are stores/sinks and give some examples at the coast?
Stores/sinks of sediment and material like:
Beaches Cliffs.
Sand dunes Wave cut platforms + notches
Spits Stumps + stacks
Bars Salt marshes
Tombolos Tidal flats
Headlands Offshore bands + bars
Bays
What are transfers/ flows and give some examples at the coast?
Processes that link the inputs, outputs + stores like:
, Mass movement Transportation
Longshore drift Wind blowing sand
Weathering Deposition
Erosion
What is an output? Give some coastal examples
Something that leaves the system like:
Ocean currents Water via evaporation
Rip tides Sediment transfers
Give some examples of sediment sources + why they are sources at the coast
Rivers- sediment transported by them
Cliff erosion- Eroded material from there
Wind- In glacial/ hot environments =wind blown sand = deposited in coastal
regions {this can lead to sand dunes}
Glaciers- if chunks of ice break off glaciers/ice sheets, they can deposit the
sediment trapped in them in the sea
Offshore sediment- sediment from offshore can be transported into the
coastal zone by waves, tides and currents
Longshore drift- from one stretch of coastline to another, as an output to an
input
Explain the formation of a wave- Wind blows over the sea surface, transfers
energy to it via frictional drag, and this forms a wave
What are the factors that affect waves?
Strength of the wind
The length of time it's blowing for
Fetch {The stretch of ocean water over which the wind blows}
Give the characteristics of a constructive wave
Flat
Low wave height
Long wavelength
, Strong swash that carries and deposits material up the beach
Low frequency {6-8 waves / minute}
Creates gently sloping beaches + a weak backwash
Give the characteristics of a destructive wave
Large wave height Weak backwash
Short wavelength Creates steep beaches
Steep wave front Strong swash that erodes beach
material + cliffs
High frequency {13-15 waves/
minute}
Describe wave refraction
The process by which waves turn + lose energy around a headland on uneven
coastlines. The wave energy is focused at the headlands, since, as the waves come
in they are high energy, and the water around headlands is shallow so they
become steep, high + short, and the part of the wave that's in deeper water moves
forward faster, causing the wave to bend or refract, being concentrated at the
headland, so it also concentrates the erosion on the headland too, which is
negative feedback
What are tides?
Changes in the level of seas/oceans caused by the gravitational pull of the moon
{energy source}. The UK experience 2 high + 2 low tides each day.
What is tidal range?
The difference between the high + low tide
What is a spring tide?
When the moon is in line with the sun and the Earth {full/new moon} =
strong gravitational pull = higher high tides + lower low tides = larger tidal
range
What is a neap tide?
