Explain how the sediment cell concept contributes to the understanding of coastal systems (8)
The sediment cell concept consists of sinks, sources and transport. The main concept is that the
sediment cell is a closed system which means no sediment is added or taken away. There are 11
sediment cells around the UK which are divided by a change in direction of the coastline. A
commonly known sediment cell is the Holderness coast sediment cell. Each sediment cell may
consist of further divided, smaller cells. In each cell there is the source. This is usually a cliff which is
being eroded leading to the addition of sediment on the beach or sea. The sediment is then
transported by longshore drift along a coastline until the waves do not have enough energy to carry
it. Thus, by a process of gravity settling, larger load is deposited first, followed by smaller rocks and
fine sediment. The location where the sediment is deposited is known as the sink and can form
beaches and berms. At low tide, the sand may be blown onto the coastline, forming sand dunes.
These processes (erosion, transportation and deposition) enhance our understanding of coastal
systems as it describes how sediment moves along a beach. However, there are factors which can
affect the natural processes of the sediment cell. For instance, human intervention such as the
construction of groynes can cause terminal groyne syndrome and can lead to an imbalance in the
natural dynamic equilibrium of sediment cells.
Evaluate the different ways coastal areas can be managed (20)
Coastal management consists of various hard and soft engineering techniques to manage coastal
erosion and flooding. Different techniques are usually appropriate for different locations depending
on the level of defence required. Various methods may also be used in conjunction to provide more
successful protection.
Hard engineering methods are commonly constructed on high-energy coastlines. These are man-
made structures typically of concrete, steel or stone, used to stop or disrupt natural processes which
in return protect the coastline from flooding/erosion. Hard engineering techniques are very effective
however are relatively expensive in comparison to other management techniques. For instance,
groynes which are fence like structures built 90 degrees to the coast, cost between £150-£200/m.
Their aim is to prevent the movement of longshore drift and cause build up of material on the beach.
This reduces the effects of erosion as the beach has a constant supply of sediment. However, this
method of management can have a negative chain effect on the rest of the coastline. A major issue
regarding groynes is that a coast may suffer from terminal groyne syndrome. This is when the
coastline further down from the groynes suffers from sediment starvation causing increased levels of
erosion. Therefore, although groynes can be useful in the immediate location, it can cause increased
erosion in other locations. Coastlines may also be managed by hard-engineering megaprojects such
as Deltawerken in the Netherlands. This is when a series of hard engineering techniques are used to
protect a coastline which is very susceptible to storm surges that can cause coastal flooding and
intense erosion. Deltawerken consists of a series of dams and sluice gates which can be closed to
shut the sea out during storm surges. The entire plan cost over US$5 billion however risks of sea
level rises means the Dutch will need to continue to raise and strengthen their flood defences to
ensure they remain effective. This is very costly however as the Netherlands are a HIC, they are able
to afford the maintenance. In comparison, an LIC would be unable to afford this level of defence and
therefore it is common that they will use sustainable coastal management.
Sustainable coastal management is when the coastal zone is managed holistically, and
environmental and ecological impacts are minimised. A common sustainable coastal management
technique is education. This is significant in locations where there is limited funding or investments
towards coastal management. For instance, this technique is prominent on the island of the
, Maldives. The organisation, Mangroves for the Future is working close with Maldivian communities
to educate them on the importance of maintaining coastal mangrove swamps as a natural defence
against coastal erosion and flooding. This is being proven to be cost-effective and very active.
However, this technique is unlikely to work independently and therefore can be used in conjunction
with other techniques to be more effective. Another technique is relocation away from coastal
location. However, this can be very expensive and difficult for people especially in countries suffering
from poverty.
Furthermore, soft engineering techniques are defence systems which work alongside natural
processes. They are commonly used where risk of erosion or flooding is not necessarily great or in
locations where the population wants to maintain the natural beauty of the coastline. For instance,
beach nourishment is a process in which beaches are artificially replenished with sediment. This can
help replace sediment lost by erosion and expand the beach so that it dissipates wave enrgy.
However, this technique is also relatively expensive and requires constant maintenance as the
sediment will regularly be washed away by waves. Another soft engineering technique is cliff
stabilisation. This is when the cliff is reconstructed to be less susceptible to mass movement.
Although this is also an expensive technique, it is subtle and does not affect any natural processes. It
is also a less intrusive technique to manage the coast in comparison to hard-engineering techniques.
To conclude, there are various different coastal management techniques which vary in their level of
effectiveness as well as appropriateness for different locations in terms of level of development and
scale of risk of erosion/flooding.
Assess whether sustainable management schemes are always the most appropriate for managing
the risks to coastlines (12)
Sustainable management schemes are methods used to manage the coastal zone holistically, whilst
minimising environmental and ecological impacts. These techniques can be effective however they
are arguably not appropriate for all coastlines. One common sustainable management scheme is
relocating which is migration from coastal and flood susceptible locations to areas inland, away from
the coastline. This method promotes living away from coastlines to limit the number of people
affected by coastal flooding. This is effective management for people however the environment is
still vulnerable to flooding and storm surges. Therefore, the environment in unprotected and
frequent storms or powerful waves can cause rapid erosion resulting in cliff recession. Moreover,
relocating may be difficult for people due to personal circumstances. Some people may not be able
to afford living elsewhere and so relocating is an issue. Also, some people may have been living at a
certain location for many years and have developed an emotional attachment to the area making it
difficult to leave and find a home elsewhere. Therefore, although relocating protects people from
severe flooding and storm surges, it does not protect the environment, and some may not be able to
afford homes elsewhere. Furthermore, another sustainable management technique is afforestation
and protests to save coastal mangroves. This is the encouragement of planting trees and saving
existing ones from deforestation. This technique dissipates wave energy during tropical cyclones and
depressions however it can take many years for trees to grow and be effective as a sustainable
management scheme. These schemes are especially appropriate for LICs as these methods are cost-
effective. However, it is unlikely these methods would be appropriate for locations susceptible to
storm surges.
We could also argue that sustainable management techniques (bottom-up) are not effective for
coastlines vulnerable to storm surges. This is due to sustainable management schemes being small
scale and not active in defending the coast in events such as storm surges. Therefore, in these
