YOU SHOULD MAKE SURE YOU KNOW THE CONTENT OF ALL THESE SLIDES AND COMPLETE ALL ACTIVITIES.

YOU SHOULD MAKE SURE YOU KNOW THE CONTENT OF ALL THESE SLIDES

AND COMPLETE ALL ACTIVITIES

You need to know the words below, check you have them

in your books.

SWASH – movement of water up the beach as a wave breaks.

BACKWASH – movement of water down the beach as water from wave returns to the sea.

FETCH – the length of the stretch of water that the waves have travelled across to reach the coast.

PREVAILING WIND – the direction the wind usually blows from.

You need to be able to describe the differences between constructive

And destructive waves.CONSTRUCTIVE WAVES BUILD THE BEACH BECAUSE SWASH IS STRONGER THAN BACKWASHDESTRUCTIVE WAVES ERODE THE BEACH BECAUSE BACKWASH IS STRONGER THAN SWASH

• HYDRAULIC POWER – The force of water and air pushed into cracks and shattering the cliff.

• CORRASION – The force of pebbles and rocks thrown against the cliff, breaking pieces off.

• ATTRITION – Pebbles rubbing together in the water and making smooth rocks.

• CORROSION – A chemical reaction that is particularly good at wearing away limestone.

YOU MUST MAKE CERTAIN THAT YOU

UNDERSTAND WHAT THE PROCESSES

DO. THEY ARE THE KEY TO SCORING

HIGH MARKS ON MANY SIX MARK

QUESTIONS. IF YOU DON’T

UNDERSTAND THEM, YOU CANNOT

SCORE MORE THAN TWO OUT OF SIX!

METHODS OF TRANSPORTHow material is carried in the water

LARGE ROCKS ARE DRAGGED ALONG THE BOTTOM.

PEBBLES BOUNCE ALONG THE BOTTOM.

TINY MATERIAL IS CARRIED ALONG IN THE WATER

SOME ROCKS WILL DISSOLVE IN THE SEA.

Look at the diagram carefully. You can see that the prevailing wind is blowing at an angle to the coast. This affects the direction of the swash. The backwash is affected by gravity and moves back towards the sea at right-angles to the coast.

This is a really important idea for the coats unit. You need to practise remembering the diagram so that you could draw it in an exam. Remember that a diagram with no labels is no good.

Without looking at the previous slide. Draw adiagram to explain longshore dirft. Underneath it, explain how longshore drift happens. Use all the words below.

ANGLE PREVAILING WIND WAVES

BREAK GRAVITY SWASH

BACKWASH RIGHT-ANGLES

TRANSPORTATION

THE WORDS ON THE PREVIOUS SLIDE ARE GREAT WORDS TO WRITE IN THE MARGIN IN THE EXAM BEFORE STARTING AN

ANSWER. CAN YOU REMEMBER THEM ALL? CLICK TO CHECK.

THERE WERE 9 TO REMEMBER!

ANGLEPREVAILING WINDWAVESBREAKGRAVITYSWASHBACKWASHRIGHT-ANGLESTRANSPORTATION

WHAT DO THE FOLLOWING WORDS MEAN?CLICK TO CHECK YOUR ANSWERS.

CORROSIONA chemical reaction that wears away rocks such as limestone.

SALTATIONMaterial bounces along to seafloor.

CORRASIONCliffs are eroded by the force of rocks thrown in the water breaking pieces off.

TRACTIONLarge rocks are dragged along the seafloor.

ATTRITIONThe smoothing of rocks and pebbles as they bash against each other in the sea.

SUSPENSIONSmall material is carried along in the water.

HYDRAULIC POWERRocks are forced apart and shattered as air and water are pushed into cracks.

SOLUTIONSome rocks slowly dissolve in the water and are carried in solution.

LOW TIDE MARK

As the notch gets deeper the overhang becomes unsupported and falls under the force of gravity. This leaves a “shelf” between high and low tide called a wave cut platform.

Corrasion attacks the cliff between these two marks the most. Hydraulic power forces air and water into small gaps force pieces of rock to break off. The notch gets deeper into the headland, leaving an overhang.

HIGH TIDE MARK

Original cliff position

Draw a diagram to show how wave cut

notches and platforms are formed.

Write a description of what happens making

sure you explain how the processes work.

Include the words below…..

High Tide Low Tide Corrasion Hydraulic Power

Overhang Notch Deeper Retreat

Weaknesses in the rock are attacked by corrosion (dissolving the rock around the weakness) and hydraulic power which shatters pieces of rock around the crack as the force of water and air pushes into the cliff.

The weakness grows into a cave over time as hydraulic power and corrasion continue to act on the cliff. Eventually the cave will cut through the headland leaving an arch.

Weathering makes the top of the arch thinner. Eventually it will collapse.

Draw a diagram to show caves, arches and

stacks are formed.

Write a description of what happens making

sure you explain how the processes work.

Include the words below…..

Weakness Corrosion Corrasion Hydraulic Power

Cave Deeper Weathering Arch

Collapse Stack

A spit is a deposition feature. For a spit to form three factors are needed. You will need to remember these and label them on any diagram about spits.

1. Shallow Water

3. An area where longshore drift occurs.

2. A sudden change in the direction of the coastline

1. Waves break on the beach at an angle. Material is washed up the beach in swash whilst gravity carries the material back down the beach in backwash. The is called longshore drift.

2. At the sudden change in coastline the longshore drift continues in the same direction through the shallow water.

3. As the water gets deeper and the river current stronger deposition stops. Wind blowing from a different direction may curve the end of the spit.

wind

river

curre

nt

LONGSHORE DRIFTDEEP WATER

PREVAILING WINDRIVER CURRENT

SECONDARY WINDHOOKED END

SHALLOW WATER

CHANGE IN DIRECTION OF THE COASTLINE

CAVE

HYDRAULIC POWER

CORRASION

HEADLAND

HARD ROCK

LONGSHORE DRIFT

DIRECTION OF COAST

SHALLOW WATER

DEEP WATER

RIVER CURRENT

HOOKED END

PREVAILING WIND

HIGH & LOW TIDE

CORROSION

CORRASION

HYDRAILIC POWER

NOTCH

OVERHANG

PREVAILING WIND

ANGLE

SWASH

BACKWASH

GRAVITY

TRANSPORTATION

STRONG BACKWASH

WEAK SWASH

BEACH DESTROYER

TALL

SHORT WAVE LENGTH

FREQUENT

COLLAPSE

WEATHERING

ARCH

HYDRAULIC POWER

WEAK

CORROSION

GROYNES – wooden fences that are at right angles to the coast. They trap material carried by longshore drift.

Direction of longshore drift

Many of the Groynes in the UK are victorian. Eventually the wood rots and they need replacing.

Groynes can be seen in Blackpool.

There may be problems further down the coast because the beach there will have less sand.

Rip Rap is an expensive way to protect the coast as large amounts of rock are needed.

Rip Rap is seen by many to be very ugly and may affect the tourism in the area if the coast is not attractive.

RIP RAP are large rocks dumped along the coast. They absorb wave energy and prevent the force of waves reaching the coast.

Rip Rap can be seen in Morecambe

SEA WALLS are built along the coastline. The are huge concrete walls. They reflect wave energy back out to sea.

Sea Walls can be seen in Bridlington

Reflecting energy may cause scouring at the base of the wall. This may result in damage to the foundations of the wall.

Sea walls are expensive to build, costing approx £10,000 per metre

BEACH NOURISMENT is a soft engineering approach to protecting the coast. Sand is added to the beach to help maintain natural protection against the sea.

The beach is built up by the extra sand and this helps keep waves away from the coastline.

A constant supply of sand is required.

Name of defence

Description of what it looks like

How it works? Disadvantages Where it can be seen?

Groynes

Seawall

Rip Rap

Beach Nourishment

Mappleton is on the Holderness Coast in East Yorkshire.

The Holderness coast has one of the fastest erosion rates in the world – an average of 2m per year.

The cliff are made of glacial till (boulder clay) and are very soft.

The threat to the main road (B1242) through the village prompted the council to protect the coast.

Grass at base of cliff helps bind the soil

Landscaped cliff to a more gentle slope. Water would roll up the cliff base rather than eat into it.

Sand trapped by rock armour.

Healthy beach at Mappleton as sand is trapped by the rock armour which keeps the waves from the cliff base.

Great Cowden is down coast of Mappleton. The beach has almost disappeared here bacause of the sand trapped at Mappleton.

Erosion increased from 2 metres per year up to 20 metres lost in one year as waves bashed the cliff 24/7. Sue Earl had to pay for the demolition of her farm here.

Which coastline is Mappleton on? Holderness

What is the cliff made of at Mappleton? Boulder Clay (Glacial Till)

Why did the council decide to protect Mappleton?

To protect the B1242

How does planting grass at the base of the cliff help?

Roots grip the soil

What has been used to trap sand from longshore drift?

Rock Armour

What was the average erosion rate along the Mappleton coast?

2 metres per year

Name the place where erosion increased after Mappleton was protected?

Great Cowden

How much did the erosion rate increase here?

20 metres lost in one year

How often did the waves reach the cliff here?

24/7

Name the farmer who had her farm demolished?

Sue Earl

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

M.G.Q.

Holbeck Hall in Scarborough fell into the sea in 1997 when the cliff slumped at the base causing mass movement.

Mudflow- occurs when the cliff become so saturated

with rainwater that the cliff collapses and is mobile

enough to flow quite quickly on to the beach.

Blackpool became popular during the industrial revolution with holiday makers from the north of England. Today it faces problems of coping with visitors and keeping its business against an increasingly competitive global market.

Problems include:

•Unemployment in winter months when attractions are closed.

•Overcrowding and congestion at peak times.

•Competition from resorts abroad with more reliable weather.

•Keeping the beach clean.

Solutions:

•Investment in street cleaning equipment and maintaining a clean beach – earning an EU Blue Flag.

•Extending the season into winter months by becoming a conference centre and marketing the illuminations.

•Providing new facilities, some of which are indoor – e.g. Pepsi Max.