15 Mark Question- Soft Engineering.

‘Soft engineering works in harmony with the natural environment and is effective in protecting the coast’.

To what extent do you agree with this view? (15)

Soft engineering is a form of coastal management that works with the natural environment while effectively protecting the coast from coastal erosion. Soft engineering’s use of natural resources and materials allows its methods to work in harmony with a coast’s natural environment. This is because the natural materials used cause little to no disruption to a beach’s appearance and environment. Soft engineering schemes can be very effective in protecting the coast, an example of this is Pevensey Bay in East Sussex. A 30 million pound coastal protection scheme was launched in 2000 at Pevensey Bay. The scheme is predicted to last for up to 25 years. Soft engineering is the main form of coastal protection featured as part of the scheme. The scheme has so far effectively protected the Pevensey Bay coast for 16 years.

Beach Nourishment is one of the methods used at Pevensey Bay. This involves using a dredger to placing up to 40,000 tonnes of new shingle onto the beach each summer in order to replace the shingle that has been lost through longshore drift. The new shingle deepens the beach which allows it to provide a buffer to incoming waves to prevent erosion such as hydraulic action happening to the top of the beach. The longer the waves have to travel along the beach the less energy they have when they reach the top of the beach. This soft engineering method also works in harmony with Pevensey Bay’s natural environment as the use of natural shingle causes no disruption to the beach’s appearance or character.

Beach Reprofiling is another method of coastal defence used at Pevensey Bay. This method uses bulldozers to move shingle back to its original position on the beach after being moved along the beach by longshore drift. Beach can be re-shaped after storms or prepared for predicted storms using this method of soft engineering. Beach Reprofiling is very effective at Pevensey Bay, at least one bulldozer is kept at the beach at all times with others available to be brought in when needed. This means that the beach’s shape can be kept intact at all times, this allows the beach to defend itself against the energy of incoming waves therefore protecting the 15,000 properties and 2 nature reserves situated alongside the Pevensey Bay coast. Beach Reprofiling also works harmoniously with the natural environment as the beach’s amenity value is not damaged as the method uses natural resources to carry out its coastal protection.

Overall I agree with the view that ‘Soft engineering works in harmony with the natural environment and is effective in protecting the coast’ and I believe that the successful protection of Pevensey Bay using soft engineering is evidence of this. However some people may argue that Hard Engineering can provide more effective methods of coastal defence such as Sea Walls, Groynes and Gabions. Coastal Areas such as Hunstanton in Norfolk have chosen to protect their beaches with methods of Hard Engineering. Although hard engineering can provide an effective short-term solution to coastal erosion in the long term its methods are unsustainable due to their expenses and maintenance needs. In addition to this hard engineering methods commonly use man-made artificial resources to protect coasts, therefore they do not work in harmony with the natural environment unlike soft engineering methods. 

Coastal Erosion- Hard engineering methods.

Groynes-

Groynes are typically wooden structures however other artificial materials can be used. These structure run from the top of the beach to the sea, they are designed to interrupt the process of Long Shore Drift. It does this by interrupting the sediment that is being moved along the beach by Long Shore Drift. These structures cost around £10,000 each and must be placed at least 200m apart from each other along the beach in order for them to work effectively.

Sea Walls-

Sea Walls are concrete wall-like structures that are often supported by iron pilings dug into the underlying rock. They are designed to prevent coastal erosion, they are either placed at the top of the beach to protect areas of importance behind the beach, or alternatively, they are placed at the foot of cliffs that are considered to be especially vulnerable to coastal erosion such as hydraulic action. Sea Walls can be flat or curved, curved Sea Walls deflect the incoming wave’s energy better and are therefore more expensive than flat Sea Walls. They can cost up to £6 million to construct per kilometre.

Gabions-

A Gabion is a strong wire cage that is filled with rocks, stones and pebbles. They protect the coast by reducing the power of the waves before that reach the cliff or coastline. Gabions reduce hydraulic action as the wave’s strength is significantly reduced when it hit the rocks inside the Gabion. Gabions can cost around £100 each. (Estimate)

Revetments-

Revetments are concrete, or alternatively wooden, structures that are built along the base of a cliff. They are slanted and act as a barrier against waves that attack the base of the cliff. They are similar in many ways to Sea Walls. The revetments absorb the energy of the waves, preventing the cliffs from being eroded by coastal erosion such as hydraulic action and abrasion. Revetments can be modified so that they have rippled surfaces, this further helps to reduce and absorb the wave energy. Depending on the material used and the distance needing to be covered, a revetment usually costs around £10,500.

Riprap-

Riprap are collections of rocks and stones that are placed against the base of a cliff. Much like gabions they are designed to absorb wave energy and reduce the amount of coastal erosion that the cliff is subjected to. They can also be placed in front of other coastal defenses to reinforce them for example sea walls. 

Coastal Erosion- Soft engineering methods.

Beach Nourishment-

This involves replacing sediment that has been lost through long shore drift or erosion. The sediment that has been moved further down the beach is moved back to its original area of the beach by local authorities. The longer incoming waves have to travel the more power they lose, this process creates a wider beach which reduces the power of the waves that hit the beach. As a result of this the amount of coastal erosion, such as hydraulic action, the beach is subjected reduces. This process usually takes place in between the tourist season, in order to reduce disruption. It costs around £3000 per 
km, the process will need to be repeated fairly regularly in order to
maintain the coastal defense.

Managed Retreat-

Managed retreat is a method whereby we allow the sea to erode and create land forms such as spits and salt marshes. Cliff erosion is allowed to occur in areas of low value farmland, farmers are then compensated for their losses. This method is cheaper than constructing more expensive coastal defenses. This can only work where the coasts of compensation are significantly less than the coasts of building coastal defenses.
It can also be beneficial to plants and animals by providing new 
habitat. The cost of this coastal defense depends

on the amount needed to compensate local people.

Sand Dunes Regeneration-

Sand Dunes often form naturally however they are fragile and come under threat because of people walking over them. Sand Dune regeneration involves using fencing to help trap sand and planting vegetation to reinforce the Sand Dune. By encouraging the formation of Sand Dunes the coastline is protected, this is because Sand Dunes intercept and absorb storm and wave energy. This costs around £2,000 per 100m.

Do Nothing-

This a method that is similar to Managed Retreat, however there are no costs at all for the local authorities. This method of doing nothing and letting nature take its course only occur in uninhabited areas of the country. These areas are not considered valuable by the government as they do not have people, houses, businesses or public buildings. This is by far the cheapest method of coastal defence as it costs the local authorities nothing.

The Demographic Transition Model.

The Demographic Transition Model:

Development indicators:

These are development indicators, they help to judge how developed a country is:

• 
  
•     Literacy rate- Total percentage of the population aged 15 and above who can read and write.
• 
  
•     Infant Mortality-the number of deaths of infants under one year old per 1,000 births.
• 
  
•     Death Rate-  The total number of deaths per 1,000 of a population in a year.
• 
  
•     Birth Rate- The total number of live births per 1,000 of a population in a year.
• 
  
•     Life Expectancy- The total number of years on average a person from a particular country is expected to live for.

Some of these development indicators contribute to calculating which stage of the

Demographic Transition Model (DTM) a particular country appears in.There are five stages to

the DTM.

My DTM revision sheet: