Coastal Change & Conflict Edexcel Geography B

Hard Rock Coast- Land's End Cornwall

• hard rock more resistant than soft rock to erosion 
• usually bare with little vegetation 
• as the softer rock is worn away it leaves headlands 
• loose rock, a few rocks which have fallen from the cliff
• high steep and rugged cliffs
• sea is clear

A soft rock coast- Holderness Yorkshire

• cliffs are high, but less rugged and not so steep
• there may be piles of mud and clay which has slipped down the cliff face
• very few rocks, some sand and mud
• sea is often brown, the colour of material from the cliff

concordant coastline: layers of different rock run parallel to the coast

discordant coastline: where bands of different rock types run perpendicular to the coast

Discordant Coastline

• often produce headlands and bay, weaker rocks such as clay are easily eroded and form bays, bands of more resistant rock protudes as headlands e.g. chalk and limestone
• caves, arches, stacks and stumps form along the headlands due to the constant attack by the ocean

Concordant Coastline

• often produce straighter coastlines
• the rate of erosion may change dramatically due to the layers of rock, if a softer layer is exposed one year

Erosional Landforms

1. Head lands and bays

• type of rock plays apart
• often form along discordant coastline due to the direction the rock forms to the beach
• weak rocks are easily eroded by destructive waves and so give rise to bays
• more resistant rock form headlands

2. Wave-cut platform

• waves erode the bottom of the cliff, this forms a notch that gradually gets bigger
• the rock above gradually loses its support and then collapses
• the debris is washed away by the waves
• the process repeats and gradually the cliff becomes steeper

Erosional Landforms

1. Caves, arches, stacks and stumps

• points of weakness such as a faults and joints are attacked particularly by abrasion and hydrochloric action
• leads to an opening which over time will form a cave
• if the cave opens up on the other side it forms an arch
• as erosion of the arch is continued the roof and pillars of the arch weakens and it collapses
• this leaves a stack seperated from the headland
• further erosion of the stack may lead to a small stump, may only be visible at low tide

Despositional Landforms

1. Beach

• constructive waves add sediment to the coastline which can form a beach
• common on low energy coastline i.e. Swanage Bay Dorset

2. Spit

• formed by longshore drift in one dominant direction 
• at the end of the beach the material being carried by longshore drift is deposited at the end of the beach 
• often curved as it is exposed to strong winds

3. Bar

• when a spit continues to grow and joins the opposite side of the coast i.e. Slapton Bay
• a 'lagoon' forms behind it

Affects on marine erosion and desposition

Affects on marine erosion

• wave erosion depends on the strength of the wave and climate change cause greater and more frequent storms which increase the rate of erosion
• coastal areas made of softer rock clay will be particularly affected by the changes and here the retreat of the coastline will be much faster

Affects on desposition features

• despositional features such as spits and bars will be under a greater risk of submergence or erosion 
• become worse as sea levels rise and erosion of beaches is affected
• heat may add more power to storms, which means the despositional features are under greater risk of being eroded away
• spits may also be breached which can cause a large gap 

• 60km of low cliffs
• made of soft easily eroded boulder clay
• fastest retreating coastline in Europe 
• coast is very exposed
• the waves are mainly destrucitve

Conflicting Views on Erosion

• erosion is a natural process and cannot be stopped
• businnesses threatened by erosion
• people don't want to move just because of erosion
• not many people live along the coast

Costs:

• loss of farmland if nothing is done
• loss of bussinesses
• cost of building sea defences
• the loss of houses
• loss of roads

Benefits:

• people do not lose homes or bussinesses
• erosion of cliffs stops
• people do not lose farms or lands
• coastline is stabalised

Plans for what areas will be protected by defences and what areas will be left alone such as the East Riding ICZM on the Holderness coastline. 

More long term and sustainable, with less imapct on the environment.

Beach Replenishement- adding sand taken from elsewhere

Costs: the sea keeps eroding it away so it has to be replaced every five years.

Benefits: looks natural, and provides a beach for tourists. 

Managed Retreat- people and activities are gradually moved back from vulnerable areas of the coast

Costs: compensation has to be paid and there is wuite a lot of disruption to people's lives and businesses.

Benefits: natural processes are allowed to happen.

Cliff Regrading- making the cliff face longer so the cliff is less steep

Costs: other methods need to be used at the base of the cliff to stop it being steepened by erosion

Benefits: method is relatively cheap, mass movement is less likely. 

• waves approach coastline at an angle
• swash pushes beach material along the beach at the same angle
• backwash drags the material down the beach at a 90 degree angle due to the force of gravity
• produces a zig zag movement, which is called longshore drift
• the finest material such as sand is easily moved along the beach
• larger material such as pebbles are heavy and not moved as far