1. N6 Geography
Lithosphere

2. Coasts

3. We are learning to…
Describe the location of coastal areas and features in the UK
Differentiate between constructive and destructive waves
Describe how the coastline is shaped by waves

4. I can… Locate areas with coastal landscapes on a map
Draw a diagram showing how waves erode the landscape
Explain the processes of erosion used by waves to shape the landscape

5. A New Ocean: Waves Explained: http://www.bbc.co.uk/programmes/p00fzssy

6. The British Isles has a coastline which amounts to 19,491 miles!
Name the coastal areas and features!

7. A – outer hebridese
B – Inner hebridese
C – North channel
D – Irish sea
E – Cardigan Bay
F – St George’s Channel
G – Bristol Channel
H – Str of Dover
J – North sea

8. Coastal Erosion
Processes of Erosion at the Coastline 1. Hydraulic Action: Waves crash against a cliff and drive water under great pressure into cracks in the rock. This pressure squeezes the air and as the wave falls back the air expands explosively, loosening pieces of rock.
2. Corrasion: Corrasion (or abrasion) occurs when stones and pebbles are picked up by waves and thrown against the cliff, causing erosion.

9. 3. Solution: Salty sea water chemically dissolves rocks
3. Solution: Salty sea water chemically dissolves rocks. This is most noticeable on chalk and limestone cliffs.
4. Attrition: Rock fragments (stones and pebbles) hit against each other and so are reduced in size.

10. Coastal landscapes are formed by a combination of erosion, transportation and deposition processes.
Waves
The force of the sea changes the coastal landscape. Waves get their energy from the wind.
The size of the wave is determined by:
The speed of the wind
The length of time the wind has been blowing
The distance of sea it has travelled over (the fetch)
The stronger the wave, the more erosion it will cause.

11. 2) Water is shallower closer to the coast.
Friction with the sea bed slows movement at the base of the circular movement of water.
Top of wave continues to move forward.
Wave height and steepness increases.
1) Deep Water: water moves in a circular motion producing the wave form.
3) Wave breaks.
Water plunges forward as swash.
Water returns as backwash.

12. Tides
At high tide the water will be deepest offshore and larger waves with more energy can reach the beach or cliff.
Storm winds at high tide have the most energy and they are responsible for most erosion and transportation.
Tidal range is the difference in the height of the sea between high tide and low tide.

13. Constructive Waves
They are created in calm weather and are less powerful than destructive waves.
They break on the shore and deposit material, building up beaches.
They have a swash that is stronger than the backwash.
They have a long wavelength, and are low in height.

14. Destructive Waves Destructive waves are created in storm conditions.
They are created from big, strong waves when the wind is powerful and has been blowing for a long time.
They occur when wave energy is high and the wave has travelled over a long fetch.
They tend to erode the coast.
They have a stronger backwash than swash.
They have a short wave length and are high and steep.

15. Task 1
Complete the blank map of the UK by labelling the coastal areas.
Copy the diagram which shows the features of a wave.
Explain the difference between a constructive and a destructive wave.
Explain the processes of erosion.

16. We were learning to…
Describe the location of coastal areas and features in the UK
Differentiate between constructive and destructive waves
Describe how the coastline is shaped by waves

17. Can I… Locate areas with coastal landscapes on a map
Draw a diagram showing how waves erode the landscape
Explain the processes of erosion used by waves to shape the landscape

18. Formation of Coastal Features

19. We are learning to… Describe the formation of headlands and bays
Describe the formation of caves, arches, stacks and stumps

20. I can…
Explain the processes involved in the formation of a headland and bay with the aid of a diagram
Explain the processes involved in the formation of caves, arches, stacks and stumps with the aid of a diagram

21. Formation of Headlands and Bays

23. Headlands and Bays can form where rocks outcrop at 900 to the coast
2. Here there are alternate bands of resistant and less resistant rock
3. Where there is soft rock (e.g. clay), erosion is rapid - and bays are formed (indent in coastline)
4. Where there is more resistant rock (e.g. chalk), erosion is much slower - headlands are formed as the harder rock is left sticking out into the sea
5. Exposed headlands then become vulnerable to destructive waves but help to shelter neighbouring bays.

24. Formation of Caves, Arches, Stacks and Stumps

25. All rocks have lines of weakness
All rocks have lines of weakness. The sea and its waves use hydraulic action, abrasion, attrition and solution to erode along any lines of weakness. Undercutting takes place all around the headland.
These lines of weakness get enlarged and develop into small sea caves.
The caves are deepened and widened on both sides of the headland until eventually the sea cuts through the headland, forming an arch.
The rock at the top of the arch becomes unsupported as the arch is enlarged, eventually collapsing to form a stack.
The stack gets eroded until only a stump remains.
Over time the stump will disappear.
As the headland retreats under this erosion, the gently sloping land at the foot of the retreating cliff is called a wave-cut platform.

26. Examples - The Dorset Coast

27. Examples –
Old man of Hoy
Selwicks Bay, Flamborough

28. Task 2 – Exam style question
With the aid of a diagram, describe the formation of headlands and bays. (8)
With the aid of a diagram, describe the formation of caves, arches, stacks and stumps. (8)

29. Perfect answer
Erosional processes: Erosion takes place due to hydraulic action — pounding waves compress trapped air in the rocks, creating an explosive blast which weakens and loosens rock fragments. Abrasion/corrasion — rock fragments thrown against the headland create a sandblasting (abrasive) action, wearing away the rock. Solution/corrosion — carbonic acid in sea water weathering limestone and chalk. Attrition — rock fragments slowly being ground down by friction from wave action into smaller and rounder pieces to form sand.

30. Perfect answer
Headland and bay: Formed by differential erosion, where softer, less resistant rocks erodes more quickly than harder, resistant rocks. A headland is an area of hard rock which juts out into the sea and a bay is a sheltered area of softer rock between headlands. Often form in areas with a discordant coastline where alternate bands of rock are found at right angles to the coast. Constructive waves build a small beach in the sheltered bay between the headlands.

31. Wave Cut Platforms

32. 1) Weather weakens the top of the cliff – rain saturating the soil / permeable rock.
2) The sea attacks any joints crack or faults in the base of the cliff through the processes of hydraulic action and abrasion (explain) forming a wave-cut notch.
3) The notch increases in size leaving the cliff overhanging and unsupported, eventually causing the cliff to collapse due to the weight above.
4) The backwash carries the rubble towards the sea forming a wave-cut platform which is a gently sloping rocky surface extending out to sea away from the cliff.
5) The cliff retreats inland due to this continued process of the cliff being eroded.

33. Task 3 – Exam style question
With the aid of a diagram, describe the formation of a wave cut platform. (8)

34. Perfect answer
Wave-cut platform: weaknesses such as joints, faults or cracks in cliffs are undercut by erosion to form a wave-cut notch the rock above overhangs over the notch and, as erosion continues, the notch enlarges until the unsupported overhang collapses due to the weight the new cliff face is then eroded and through time, the cliff retreats inland, leaving a gently-sloping rocky surface called a wave-cut platform, which extends out to sea away from the cliff the platform is abraded by rock materials, with rock pools and pot holes forming, evident at low tide

35. Processes of Transportation
Sediments are moved up and down the beach (swash and backwash).
Sediments are moved along the beach by longshore drift.

36. The water which rushes up the beach is called swash.
Backwash: As the wave loses its momentum, energy is transferred back to the sea – this return flow is called backwash.
Swash:
The water which rushes up the beach is called swash.

37. Long Shore Drift is caused by coastal
transportation and deposition where
material is moved along a coastline by
waves.
Waves often approach the coast at an angle carrying material with them.
The swash carries material onto the beach.
When the backwash drags material out to sea, it travels at right angles to the beach down the steepest gradient.
This movement will gradually transport material laterally along the coast.

38. Bars and Tombolos
A bar is a ridge of sand that blocks off a bay or river mouth. A lagoon is created behind the bar in a bay where there is no river. A tombolo is a bar of deposited material linking the mainland to an island.

39. Landforms of Deposition
Depositional features produced by longshore drift include spits, bars and tombolos.

40. The diagram shows the building of a spit by longshore drift across the mouth of a river.
Sandspits often have a curved or hooked end as a secondary wind and wave direction curves the end of the spit as waves strike from this second and different direction.
A series of such hooks can develop over time.
The spit creates an area of calmer water, sheltered by the spit.
A lagoon, salt marsh and finally dry land can develop in this sheltered area.

41. Spits
1) Longshore drift moves large amounts of material along the beach until there is a sudden change in the direction of the coastline. The sand keeps on moving in the original direction, even though there is not a coastline to follow.
2) The sea has to be relatively shallow and sheltered allowing the accumulation of sand usually beyond a headland.
3) Sometimes a curve develops if the on- shore wind changes direction.
4) Spits can become permanent if the prevailing wind picks up sand and blows it inland forming sand dunes.

42. Bars and Lagoons
A bar is a barrier of sand stretching right across a sheltered bay.
It usually stretches across the bay due to the absence of any large river that might wash it away.
It can cut off a lagoon to the landward side.
A lagoon is a body of brackish water- part salty, and part fresh. It often supports specialised plants and animals, and is protected as a nature reserve.

44. Tombolo
If a bar links up with an off-shore island, it creates a tombolo. Chesil Beach- one of the most famous bars in the UK has a tombolo called Portland Bill.

45. Task 4 – Exam style question
With the aid of a diagram, describe the formation of a sandbar and tombolo. (8)

46. Perfect answer Depositional processes:
the deposition features are caused by the process of longshore drift (1), where waves, driven by the prevailing wind, push material up the beach; known as the swash (1 mark)
the returning backwash is dragged back by gravity down the beach at right angles (1 mark).

47. Perfect answer Sand bar:
formed when a spit grows across the entrance to a bay, connecting two headlands (1), enclosing a sheltered lagoon behind it (1 mark)
this happens when there is no strong flow of water from a river into the sea (1) and through time, this stagnant lagoon water is infilled by deposition (1 mark)
bars form when there is a change in direction on a coastline(1), which allows a sheltered area for deposition (1 mark).

48. Perfect answer Tombolo:
formed when a spit extends out from the mainland, connecting to an island (1 mark).

49. Beaches
Beaches are formed of sand and shingle. They form where:
- Enough sediment is available from cliff erosion or offshore deposits.
- Longshore drift maintains a constant movement of sediment along the coast.
- Waves do not have enough energy to transport sediment because the water is too shallow or sheltered (such as in a bay).
The size, shape and height of a beach depends on the type of the beach material and the dominant type of wave.

50. Coastal Management
Successful management of coastal areas depends on understanding the different uses of coastal land and the physical processes impacting on the coast, such as erosion and longshore drift.
Techniques for managing these physical processes can be divided into hard engineering options (such as building sea walls) and soft engineering options (such as beach nourishment and managed retreat).

51. Coastal Management Strategies
As coastal tourism grows, people increasingly attempt to control the effects of the sea.
Main reasons for coastal management are: to protect the coast from sea erosion to increase the amount of sand on the beach.

52. Groynes
Wooden “fences” built at right angles to the coastline Aim to stop the movement of material along the beach due to longshore drift and to build up the amount of sand on the beach.
Need replacing every 25 years or so.

53. Gabions
Large steel mesh cages filled with large rocks. Aligned either at right angles or parallel to the coastline. Aim same as wooden groynes or rock armour. Need replacing every 20–25 years due to steel rusting away.

54. Sea Walls Often built in front of seaside resorts Very expensive and need replacing after about 75 years. Aim to completely block waves and their effects. The beach in front of them may erode.
Socially reassuring for local residents.

55. Rip Rap / Rock Armour Large boulders, of 10 tonnes or more, used as a sea wall. Gaps between the rocks allow water through so energy of the waves is effectively dissipated. Boulders must be big enough to withstand being eroded themselves.

56. Management Strategies
Physical management of the coast attempts to control natural processes such as erosion and longshore drift.
Hard Engineering
Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.

57. Waves in Porthleven, Cornwall during a storm
Type of Defence
Pros and Cons
Building a sea wall
A wall built on the edge of the coastline.
Advantages
Protects the base of cliffs, land and buildings against erosion. Can prevent coastal flooding in some areas.
Disadvantages
Expensive to build. Curved sea walls reflect the energy of the waves back to the sea. This means that the waves remain powerful. Over time the wall may begin to erode. The cost of maintenance is high.
Waves in Porthleven, Cornwall during a storm

58. Building groynes
A wooden barrier built at right angles to the beach.
Advantages
Prevents the movement of beach material along the coast by longshore drift.
Allows the build up of a beach. Beaches are a natural defence against erosion and an attraction for tourists.
Disadvantages
Can be seen as unattractive.
Costly to build and maintain.
Rock armour or boulder barriers
Large boulders are piled up on the beach.
Absorbs the energy of the waves. Allows the build up of a beach.
Can be expensive to obtain and transport the boulders.
Hopton Sea Wall, Norfolk
A boulder barrier in Nice, France

59. Soft Engineering Options
Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment.
There are two main types of soft engineering.
Beach management
This replaces beach or cliff material that has been removed by erosion or longshore drift.
The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists.
It is a relatively inexpensive option but requires constant maintenance to replace the beach material as it is washed away.

60. Managed retreat
Areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to be of low value - eg places not being used for housing or farmland.
The advantages are that it encourages the development of beaches (a natural defence) and salt marshes (important for the environment) and cost is low.
Managed retreat is a cheap option, but people will need to be compensated for loss of buildings and farmland.

61. Case study- the Dorset coast
Land uses

62. Oyster, mussel farming and fishing takes place at Poole Harbour.
The relative importance of land uses will vary, depending on the nature of the rocks and the physical landscape. Forestry will be more important in a glaciated area, such as the Lake District, than in a coastal area like the Dorset coast.
Three land uses which are important on the Dorset coast are: recreation and tourism, farming, and industry. The most important being tourism.
Farming
A warm, sunny climate with fertile clay soils on the flat land behind the coast provides opportunities for both arable and pastoral farming.
Oyster, mussel farming and fishing takes place at Poole Harbour.

63. Oil - Britain’s sixth-largest oil field is located at Poole Harbour.
Industry
There are different types of industries located along the Dorset coast:
Oil - Britain’s sixth-largest oil field is located at Poole Harbour.
Quarrying – high quality limestone is quarried on the Isle of Portland.
Sheltered harbours, eg Portland Harbour, which provide direct access to the English Channel – a major shipping route for imports and exports to and from Europe.
The Bournemouth Conference Centre is a service industry that helps to provide year-round jobs.

64. Recreation and tourism
The Dorset coast has many resorts, eg Swanage, providing tourist services including hotels, souvenir shops and restaurants.
Beautiful beaches such as Chesil Beach enable sunbathing and beach sports to take place.
The Dorset coast provides opportunities for different water sports. These include swimming, water skiing, windsurfing and yachting.
There are a number of historic attractions which bring visitors to the area. These include Corfe Castle, Thomas Hardy's cottage and a number of historic ruins. Activities also include fossil hunting, and the unusual geology of the area enables educational groups to study a variety of rock types.
The area along the Dorset coast has many coastal footpaths, eg the South West Coast Path where walkers can enjoy the stunning and varied scenery. People come to see and photograph landscape features such as Lulworth Cove, Durdle Door, Old Harry and Tilly Whim Caves.
The coastline also has diverse wildlife, because of the variety of habitats that are formed here such as sand dunes, lagoons, salt flats and calm bays. Durlston Head is famous for bird watching, whilst Brownsea Island Nature Reserve is home to red squirrel and wildfowl.

65. Renewable energy
There is the potential to generate electricity through wind and wave power in this area, in addition to nuclear power stations as there is plenty of sea-water to cool the reactors.

66. Land use conflicts and solutions
Due to the variety of different land uses, disagreement inevitably occurs. Most of this conflict is due to the mass influx of tourists to the region, especially during summer months. As there are so many different landowners and land users many conflicts arise, various management strategies are designed to minimise these conflicts.

67. Problems Solutions Conflict 1: Locals vs Tourists
Increased traffic congestion especially in 'honeypot' areas such as Corfe Castle
A steam railway line from Swanage to Corfe allows sightseers access and minimises congestion on the road
Increased traffic leads to a rise in noise and air pollution
Train lines, bus routes, cycle paths and boat trips offer alternative forms of transport
Unsightly footpaths and erosion of sand dunes because of the number of visitors
The National Trust and Dorset Wildlife Trust buy and manage land, eg surface footpaths
Increase in litter and fires especially on the beaches, eg Chesil Beach
Local authorities fine for littering or dumping. Voluntary litter picks arranged
Fragile wildlife habitats may be destroyed by walkers
Replant marram grass to conserve vegetation and sand dunes at Sites of Special Scientific Interest, eg Studland
Wildlife is disturbed on the beaches
To protect wildlife, nature reserves such as Brownsea Island have been created (National Nature Reserves)
Second home ownership increases, causing local first time buyers to struggle to get on the property ladder
National Government offer help to first time buyers through affordable home ownership schemes

68. Problems Solutions Tourists vs Tourists
There are about 18 different land users in Poole Harbour and 4,000 boats use the area during peak periods
Zoning of areas ensures that different activities are kept apart, eg at Poole Harbour. Speed limits have been put in place
Tourist facilities such as car parks, camp/caravan sites and marinas spoil the look of the coast
World Heritage Site Status allows local authorities to protect the coast from over-development with strict planning controls
Swimmers and sunbathers may be disturbed by the noise of motor boats
An Aquatic Management Plan encourages quiet areas (zones)
Anglers, eg at Chesil Beach may be disrupted by activities such as water skiing
Public education schemes, eg guide books, leaflets and signs are designed to promote responsible tourism
As many as 20,000 visitors can visit Studland beach on a hot day in the summer
Local authorities comply with the EU Blue Flag Scheme on beach quality
Visitors' dogs can dirty the beaches and footpaths
Poop scoop schemes have been set up to stop dogs fouling on the beach

69. 2011

70. 2011

72. 2010

73. We were learning to…