Presentation is loading. Please wait.

Presentation is loading. Please wait.

Using last lesson can you answer the following questions about Happisburgh? 1.What is the stretch of coastline Happisburgh is on? 2.Which direction is.

Similar presentations


Presentation on theme: "Using last lesson can you answer the following questions about Happisburgh? 1.What is the stretch of coastline Happisburgh is on? 2.Which direction is."— Presentation transcript:

1 Using last lesson can you answer the following questions about Happisburgh? 1.What is the stretch of coastline Happisburgh is on? 2.Which direction is the camera pointing? 3.What is happening at Happisburgh? 4.What are the effects socially? 5.What are the effects economically?

2 Monday, October 19, 2015 Learning objectives; To define, describe and evaluate different types of coastal engineering To be able to describe what coastal hard engineering is and list some methods. (Grade G to D) To be able to explain the advantages and disadvantages of hard engineering. (Grade C to A) To be able to justify which form of hard engineering is the most sustainable (Grade B to A*) How can coasts be protected?-Hard engineering

3 Coastal protection is not always popular. It is often very expensive-costing millions of pounds- and construction can be messy and disruptive. Furthermore not everyone agrees that the coast should be protected. There are two main methods of protection; hard engineering and soft engineering. Hard engineering involves using structures made of solid materials such as steel concrete or rocks. The main idea is to stop the waves eroding the coast. However as these structures are made of hard materials, they can be very costly to construct especially when a whole coastline requires protection! Task- In your own words can you explain what hard engineering is? To be able to describe what coastal hard engineering is and list some methods. (Grade G to D)

4 Complete the table by passing the different types of hard engineering around the room. To be able to explain the advantages and disadvantages of hard engineering. (Grade C to A

5 The sea wall is a concrete barrier along the coast which absorbs the energy of the waves. Some can be curved in order to deflect the power of the wave. Sea walls are very effective at protecting the coastline and will prevent erosion, as long as they are maintained and repaired. The maintenance and repairing can be very expensive. The initial cost to build them is also expensive (3000-5000 per meter). They last around 100 years, however often deflecting the waves can make the base of the wall weak and therefore they require constant maintenance throughout this period. The sea wall also looks quiet ugly and not natural.

6 Groynes are wooden fences or walls made from piles of rocks built out into the sea. They reduce the rate at which longshore drift carries material along the beach by trapping it on one side. This extra beach is then able to protect the coast from the sea. By preventing the sand from moving down the beach can cause erosion rates to increase further down the coast. They cost around £1000 per meter if they are wooden and £1000 per cubic meter for rock. Their average life span is around 30-40 years.

7 Rip-rap is made from granite or other hard rocks. They are placed at the base of a cliff to absorb the energy of the waves but let the water drain through them. These are relatively cheap at £1000 per cubic meter and lasting around 120 years. They also use natural resources-rocks. However they still let water through so some erosion takes place and they look environmentally ugly. They are also easily moved by the waves.

8 Gabions are wire cages filled with boulders, usually at the rear of the beach to keep the beach together. They protect from waves and encourage sand dunes (mounds of sand with plants) to form. Gabions are more of a short term measure as they are easily destroyed by the waves- the cages are easily rusted. They last on average 5-10 years and cost around £50 per cubic meter.

9 Revetments are a sloping concrete or wooden defence facing the sea. They absorb the waves energy. The wooden structures also trap the beach material. They absorb the waves energy. The older wooden structures last about 10 years and the concentre ones around 30. They are less durable than a sea wall and so may need replacing quicker. They also do not give total protection to the base of the cliff, and will need replacing faster than a concrete sea wall. They also cost around £800-1200 per metre.

10 Off shore break waters are built parallel to the coast, off the coast from rock. Waves are forced to break before they reach the shore. This reduces the waves energy. They are very expensive at around 1.3 million pounds for one, however effective at reducing the energy of the waves. As they are out to sea they do not spoil the beach. However being out at sea means they can be tricky to maintain.

11 And now for the opposite Soft engineering

12 Monday, October 19, 2015 Learning objectives; To develop a greater understanding of how the coast can be protected. To develop a greater knowledge of the advantages and disadvantages of soft engineering. To be able to describe what coastal soft engineering is and list some examples. (Grade G to D) To be able to explain the advantages and disadvantages of soft engineering. (Grade C to A) To be able to justify which form of engineering is the most sustainable. (Grade B to A*) How can coasts be protected?-Soft engineering

13 Using the first part of the lesson, can you identify the following types of hard engineering and given one advantage and disadvantage of each? Which two forms of hard engineering are missing?

14 Different stakeholders are not always happy with hard engineering along the coast. It is often felt that it is an unsustainable method of management. This is because they often cost a lot of money, require constant maintenance and harm the environment. Soft engineering methods try to work with the physical and natural processes within an area rather than building large man made structures to protect the land from wave attack. One of the most successful ways of preventing erosion is preserving a wide gentle sloping beach that can absorb most of the wave energy. Soft engineering methods are usually based on preserving and managing the beach. Task- In your own words can you explain what soft engineering is and how it is sustainable? To be able to describe what coastal soft engineering is. (Grade G to D)

15 Complete the table by passing the different types of soft engineering from table to table. To be able to explain the advantages and disadvantages of soft engineering. (Grades C to A)

16 Beach replenishment or beach nourishment is the process by which sand is replaced along the beach. Replenishing the beach makes the beach more effective at dispersing the energy of the waves. It replaces the material lost by longshore drift. As it does not prevent longshore drift beach replenishment has to be continuously carried out, making it expensive. It is done so through taking material from the sea bed and dumping it onto the shore. This involves the use of a dredger which is noisy and upsets tourism and kills marine life from the sea bed. It does however avoid the negative effects of hard engineering structures such as sea walls.

17 Beach profiling involves shaping the beach in a particular way so that it absorbs more energy during storms. During storms destructive waves tend to move the sediment down the beach towards the sea. This makes the cliff vulnerable to wave attack and therefore erosion because there is less beach protecting it. Bulldozers move the beach material back up the beach and shape if to give a gentle curve which will reflect wave energy. Beach profiling gives the beach a continued natural look. However using bulldozers along the coast is noisy and will scare wildlife. Furthermore the sea constantly changes the shape of the coast so it needs carrying out regularly.

18 Managed retreat involves allowing the coast to take back the land, by removing existing sea defences and allowing the land behind them to flood. Overtime the land will become marsh land allowing habitats to form. The marshland will also act as a natural sea defence protecting the land behind it from erosion. This is then a fairly cheap sea defence. Managed retreat allows land to flood and become eroded and some people may not agree over which land should be flooded. This causes conflict.

19 Beach recycling involves moving material from one end of the beach where it has been deposited back to the other end where is has been eroded. This happens three times a year. By carrying out beach recycling no material is needed to be dredged from the sea. Also it ensures that the beach has an even profile and no particular point is subject to wave attack. However it does have to be carried out 3 times a year which makes it costly. Putting large trucks on the beach 3 times a year disturbs coastal wildlife and puts tourists off coming to the beach, which has economic impacts for the area.

20 Encouraging salt marshes and mudflats means allowing some parts of the coast to flood in order to encourage vegetation to grow. Salt marshes and mud flats help absorb the wave energy which reduces their impact on the cliffs. By allowing small areas of the coast to flood and develop vegetation other land is protected from flooding. This will therefore also help manage rising sea levels. Salt marshes are also great for wildlife. However some land is required to flood and this can sometimes mean the loss of homes and businesses depending on the area.

21 Beach drainage involves taking the draining the excess water from underneath the beach using a drain pipe. By draining the water the sediment is allowed to dry and the beach can become more easily built up. This sand then acts as a natural buffer to the waves to prevent erosion. However although this is very natural, drain pipes have to be installed and maintained and this can be costly over long periods of time.

22 You are part of a local government for a village that is on the coast. A sea wall has already been used, and this has created lots of tension because it has to be constantly maintained and has upset the wildlife. You have been given 2 million pounds to spend. Do you: a)Repair the sea wall for another 10 years. b)Pay for beach replenishment in the winter and summer for 5 years. Think carefully about the sustainability of your answer. To be able to justify which form of engineering is the most sustainable. (Grade B to A*)

23 You are part of a local government for a village that is on the coast. A sea wall has already been used, but has recently been damaged beyond repair by coast erosion. You have been asked by the Mayor to select what you think is: a) The best hard engineering option available and b) The best soft engineering option available. She has asked you to consider cost, effectiveness and sustainability when making your decision To be able to justify which form of engineering is the most sustainable. (Grade B to A*)

24 Exam question Explain why sea level is expected to rise (3 marks) from 2010 both higher and foundation Use a case study to describe the economic effects of coastal flooding (4 marks) also 2010 both papers


Download ppt "Using last lesson can you answer the following questions about Happisburgh? 1.What is the stretch of coastline Happisburgh is on? 2.Which direction is."

Similar presentations


Ads by Google