Assess how local conditions can lead to a range of contrasting features on UK coastlines
[20]
There are multiple local conditions which can determine the features which develop along
the coastline. These conditions include, the fetch, the coast alignment and the geology of
the coastline.
Firstly, the local fetch is extremely important in affecting the height and strength of the
waves, which therefore leads to determining whether a coastline is advancing or retreating.
The fetch can be defined as the length of open water in which the wind has travelled over.
The wind duration is also key along with the fetch, wind duration is length of time the wind
is blowing for. Finally, the wind speed could be said to be the most important factor in
determining the type of features developed along a coastline, as even if there is a long fetch
and long wind duration the waves created could still be constructive waves. Therefore, the
type of wave developed is dependent on the local wind speed, and therefore the effect that
waves can have on a local coastline is dependent on the local conditions explained above. If
fetch, wind duration and wind speed is high then the waves developed will be extremely
erosive through processes such as hydraulic action, and therefore cause the coastline to
retreat and features such as wave cut platforms and headlands will form. However, if the
fetch, wind duration and wind speed are all minimal then deposition of material will occur
as constructive waves will develop and therefore advancing the coastline, with mudflats and
salt marshes forming. However, it is clear from the arguments presented above that wind
speed is the most important local condition that helps to create a range of features on a
coastline, as the waves created on a coast are dependent on the wind speed.
A second important local condition for shaping the coastline is the geology of the coast.
When the geology is perpendicular to the beach, this is called a discordant coastline and
multiple different types of rock are exposed to the sea. With this type of geology, it is easy
for headlands to be created as, the weaker rock such as clay will be exposed and eroded at
quicker rates than a more resistant rock like chalk. Headlands are formed when there is one
layer of resistant rock, then surrounded by two layers of weaker rock either side, which
allows for the weaker rocks to be eroded by hydraulic action and causing that part of the
coastline to retreat leaving the resistant rock to remain and forming a headland. This type of
discordant geology is present along the coast in Flamborough Head, Yorkshire where
multiple headlands can be seen. Local conditions such as local temperatures can then affect
what happens after the headland is formed. Actions such as freeze-thaw weathering attack
the weaker joints and fissures within the headland, and wave refraction concentrates wave
energy onto the headland. Furthermore, these processes then cause features such as caves,
arches, stacks and stumps, such as Old Harry’s Rocks. Therefore, it is clear that the geology
of the coast plays an important role in creating contrasting features along the coastline, as
the rate of erosion tends to be dependent on the type of geology present.
A final local condition which can create contrasting coastal features is the type of coast and
whether the coast is drift aligned or swash aligned. Swash aligned beaches experience
minimal longshore drift and founded on irregular coastlines where the waves hit sections of
the coast head on. Features found on swash aligned beaches include berms, ridges, runnels
and cusps. Whereas drift aligned beaches are parallel to the direction of the dominant
[20]
There are multiple local conditions which can determine the features which develop along
the coastline. These conditions include, the fetch, the coast alignment and the geology of
the coastline.
Firstly, the local fetch is extremely important in affecting the height and strength of the
waves, which therefore leads to determining whether a coastline is advancing or retreating.
The fetch can be defined as the length of open water in which the wind has travelled over.
The wind duration is also key along with the fetch, wind duration is length of time the wind
is blowing for. Finally, the wind speed could be said to be the most important factor in
determining the type of features developed along a coastline, as even if there is a long fetch
and long wind duration the waves created could still be constructive waves. Therefore, the
type of wave developed is dependent on the local wind speed, and therefore the effect that
waves can have on a local coastline is dependent on the local conditions explained above. If
fetch, wind duration and wind speed is high then the waves developed will be extremely
erosive through processes such as hydraulic action, and therefore cause the coastline to
retreat and features such as wave cut platforms and headlands will form. However, if the
fetch, wind duration and wind speed are all minimal then deposition of material will occur
as constructive waves will develop and therefore advancing the coastline, with mudflats and
salt marshes forming. However, it is clear from the arguments presented above that wind
speed is the most important local condition that helps to create a range of features on a
coastline, as the waves created on a coast are dependent on the wind speed.
A second important local condition for shaping the coastline is the geology of the coast.
When the geology is perpendicular to the beach, this is called a discordant coastline and
multiple different types of rock are exposed to the sea. With this type of geology, it is easy
for headlands to be created as, the weaker rock such as clay will be exposed and eroded at
quicker rates than a more resistant rock like chalk. Headlands are formed when there is one
layer of resistant rock, then surrounded by two layers of weaker rock either side, which
allows for the weaker rocks to be eroded by hydraulic action and causing that part of the
coastline to retreat leaving the resistant rock to remain and forming a headland. This type of
discordant geology is present along the coast in Flamborough Head, Yorkshire where
multiple headlands can be seen. Local conditions such as local temperatures can then affect
what happens after the headland is formed. Actions such as freeze-thaw weathering attack
the weaker joints and fissures within the headland, and wave refraction concentrates wave
energy onto the headland. Furthermore, these processes then cause features such as caves,
arches, stacks and stumps, such as Old Harry’s Rocks. Therefore, it is clear that the geology
of the coast plays an important role in creating contrasting features along the coastline, as
the rate of erosion tends to be dependent on the type of geology present.
A final local condition which can create contrasting coastal features is the type of coast and
whether the coast is drift aligned or swash aligned. Swash aligned beaches experience
minimal longshore drift and founded on irregular coastlines where the waves hit sections of
the coast head on. Features found on swash aligned beaches include berms, ridges, runnels
and cusps. Whereas drift aligned beaches are parallel to the direction of the dominant
