GEOGRAPHY GCSE : COASTS UNIT

COASTS : Areas to revise / Areas you can expect Exam Questions on. Weathering and Erosion are important physical processes in coastal areas. Describe and explain the processes of weathering and erosion that change coasts (FLAMBOROUGH HEAD, MAPPLETON) Physical processes, rock type and structure all give rise to distinctive coastal landforms Use examples to explore the landforms associated with ‘hard’ coastlines including headland, bays, caves, arches, stacks, wave-cut platforms (FLAMBOROUGH HEAD), and ‘soft’ coastlines including slumping & landslides (MAPPLETON, TUNSTALL) The movement and deposition of beach material creates distinctive landforms Use examples to explore the processes of longshore drift and the formation of beaches, bars and spits (MAPPLETON, HORNSEA, WITHERNESEA, SPURN HEAD) Some areas are protected from the effects of coastal erosion Use examples of Shoreline Management Plans to show why some coasts are protected rather than others, and how decisions are made to protect some coasts (HOLDERNESS) There are different methods that can be used to protect coasts from erosion. Know the difference between ‘hard’ and ‘soft’ engineering strategies. Use examples to show how ‘hard’ engineering works (sea walls, rock armour/rip-rap, gabions, tetrapods, groynes, cliff drainage. (WITHERNSEA, HORNSEA, MAPPLETON, EASINGTON, JAPAN) Some coastal areas are protected by environmental management Use an example to show the environmental value of some coastal landscapes, and the strategies used to protect these valuable coastal environments. (SPURN HEAD, GREEK ISLANDS – TURTLES, GREAT BARRIER REEF) Coastal areas are multi-use areas which provide opportunities for a number of human activities Describe and explain the reasons for the growth of population in coastal areas. (TOKYO – JAPAN, ISLE OF WIGHT, HUMBER ESTUARY & EAST YORKSHIRE COAST) Use an example to show the range of human activities to be found in coastal areas and explain why they are attracted to the coast. (HUMBER ESTUARY) Coastal areas can be Growth Poles for economic growth Use an example to show the coast is an important location which encourages economic development. (DUBAI, BELIZE CARIBBEAN RIVIERA) There are frequently conflicts of interest at the coast and this creates a need for management strategies to solve the issues Use examples to examine issues arising out of conflicts of interest between economic development and the need for conservation in coastal areas. Give examples of solutions to protect coastal areas (HUMBER, TURTLES & GREEK ISLAND, GREAT BARRIER REEF – AUSTRALIA) The sustainable future of coasts needs the whole of the coast to be managed as a system Use an example of Integrated Coastal Zone Management to explore the various pressures on the coastal environment and the strategies being used to ensure the long-term sustainability of the area (NE COAST OF AUSTRALIA – GREAT BARRIER REEF) Protecting coastal areas from the increasing risk of erosion and flooding will require the best long-term management of the coast. Use an example of Managed Coastal retreat to describe how it operates, explain how it helps protect the coast, and evaluate how effective it is in dealing with coastal flooding when taking the advantages & disadvantages into account. (MANAGED RETREAT ON THE HUMBER N. BANK) Examine how monitoring and planning might be used to manage the threat of sea level rise (RESPONSE PLAN, N. YORKSHIRE COAST – ROBIN HOODS BAY V REIGHTON BAY

Coasts : Features of Erosion / Headlands and Bays 1 Key Terms : Headland Bay Resistant Rock Less resistant rock Erosion Peninsula (headland surrounded on 3 sides by water) Example / Case-Study : Flamborough Head (Headland) Bridlington Bay Holderness coast (Bay) Where 2 or more different types of rock exist at the coast, it is likely that one is more resistant than the other to erosion by the sea. The less resistant rock is eroded more quickly, leading to BAYS. The more resistant rock is eroded – but more slowly, leaving it as a HEADLAND Possible Questions : Describe different features of erosion at the coast Why do some areas of coastline jut out more than others? Weblinks : Watch this BBC video clip on Headlands and Bays

Coasts : Features of Erosion / Headland and Bays 2 Key Terms : Chalk (more resistant rock) Boulder clay (less resistant) Ice-sheets Coastal retreat In East Yorkshire the more resistant rock is the CHALK which is in the North of the coast and forms the HEADLAND of Flamborough Head The less resistant rock is not really a ‘rock’ at all, but the deposits from the last advance of the Ice-sheets in the last ICE-AGE. As the ice-sheets melted, they deposited the clay and boulders they carried inside them. Holderness is made up of much less resistant BOULDER CLAY which forms one of the fastest eroding coasts in the world at over 3m a year. As a result of the rapid erosion of the Boulder Clay, over 2 miles of coast has been worn away since Roman times leading to the loss of much farmland and many villages. Example / Case-Study : Flamborough Head (Headland) Holderness coast (Bay) Lost village ‘Owthorne’ – east of Withernsea Possible Questions : Describe the effects of coastal erosion. What are the impacts of coastal erosion on human activity? Weblinks : http://www.fortunecity.com/greenfield/ecolodge/25/erosion.htm Watch this BBC video clip on Holderness boulder clay

Coasts : Features of Erosion / Joints, Caves, Arches, Stacks, Stumps, Wave Cut Platform 3 At Flamborough Head there are distinctive FEATURES of EROSION. These show the headland is being slowly eroded. They also provide attractions for tourists who want to explore the caves, rock pools and arches. Sea birds nest in the joints on the cliff faces and bats may nest in the roof of caves. But they can be hazardous with rock falls from the cliffs, people slipping on the wave-cut platform, and ships running aground on Stumps at high tide Key Terms : Joint  Cave  Arch  Stack  Stump  Wave-Cut Platform. EROSION PROCESSES : CORRASION (ABRASION) CORROSION (Solution) HYDRAULIC ACTION FREEZE-THAW ACTION UNDERCUTTING 4. The roof of the Arch is above the direct action of waves, but may get thinner due to sea-spray dissolving the rock due to CHEMICAL ACTION (corrosion) and from FREEZE-THAW action in winter when water enters small joints and expands when it freezes, widening the joints 3. If the cave is one side of a Headland, it may ERODE through to the other side to form an ARCH. Example / Case-Study : Flamborough Head The chalk stack at Selwicks Bay is called ADAM 5. Once the roof of the Arch is too thin to support itself it may collapse leaving a STACK. This pillar of rock is eroded at the top by Corrosion and Freeze-Thaw action, and at its base by CORRASION (also called ABRASION) when rocks are smashed against the rock face by storm waves causing UNDERCUTTING. 2. The Joint is enlarged (made bigger) into a CAVE. The sea does this through HYDRAULIC ACTION, and CORROSION (Solution). Possible Questions : Describe and explain features of coastal erosion. What processes take place at the coast to give distinctive landscape features? Weblinks : http://www.geography.learnontheinternet.co.uk/topics/flamborough.html Watch this BBC video clip on Stacks Or this BBC video clip on Stacks 1. The process starts with a small JOINT – a weakness in the rock which forms a crack. Chalk has many joints as it is not a particularly strong rock 7. Eventually the Stump is worn down to leave a rock platform where the cliff used to be – known as a WAVE-CUT PLATFORM full of rock pools and uncovered at low tide 6. The Stack is worn down to leave a STUMP which just emerges at low tide.

Coasts : Features of Erosion / Joints, Caves, Arches, Stacks, Stumps, Wave Cut Platform 4 F A SMALL CAVE D JOINT LARGE CAVE C WAVE-CUT PLATFORM G E STUMP B ARCH STACK

Coasts : Processes of Erosion / How the sea wears away ‘Hard’ Coasts 5 Key Terms : Weathering Erosion Corrasion (abrasion) Hydraulic action Attrition Corrosion (solution/chemical action) Freeze-thaw action Weathering : how rock is broken up and disintegrates, ready to be removed by waves. Possible Questions : Distinguish between ‘weathering’ and ‘erosion’ at the coast. Which of the following processes are ‘erosion’ and which are ‘weathering’? Erosion : rock is worn away and transported away at the same time Weathering Erosion Freeze-Thaw action Where water (from rain or sea spray) enters joints above the water level, freezes on a cold night, ice expands and makes the joint wider Corrasion (Abrasion) Where chunks of rock are flung into cliffs by storm waves chipping bits off the cliff Corrosion (solution / chemical action) Where acids and salts in sea-water or sea-spray cause rocks to dissolve or disintegrate. Hydraulic Action Where air is compressed into a joint as a wave breaks against a cliff, then expands explosively as the wave recedes – vibrating the rock, making joints wider Attrition When rocks and pebbles on the shore wear each other down and smooth off rough edges as they roll against each other as waves roll them Example / Case-Study : Flamborough Head (Headland) Weblinks: Watch this BBC video clip on Weathering Watch this BBC video clip on Erosion

Coasts : Processes of Erosion / next 2 slides – which is ‘weathering’ and which ‘erosion’? 6 Corrasion (Abrasion) Where cliff faces are worn away by rocks hitting them by the force of waves. Corrosion When salts and other acids in seawater slowly dissolve the chalk (also known as solution) Hydraulic Action When storm waves crash against a cliff, they compress air into joints in the rock. As the wave recedes the air is released with explosive force. This vibrates the cliff, makes joints bigger, and breaks bits of rock away.

Attrition Where the rocks wear against each other as they roll over each other by the waves - making them smoother and smaller 7 Freeze-thaw action Water (rain or wave spray) seeps into cracks in the rocks, freezes on cold nights and expands. This force the joint apart. Over many years chunks of rock will be broken off. Chemical action Rain is a weak acid – and will dissolve chalk easily as it falls on the exposed roof of the arch. Along with the salt sea spray this dissolves the roof

Coasts : Features of Erosion / ‘Soft’ Coastline erosion – Holderness Boulder clay 8 The less resistant BOULDER CLAY of Holderness is removed from below, but made ready for erosion from above. Rain soaks into the heavy clay and does 2 things: a) Rainwater makes the clay even heavier and likely to slump b) Rainwater lubricates any weaknesses in the boulder clay forming a SLIP PLANE which front portions of cliff SLUMP down. At high tide crashing waves wear away the cliff at the base from CORRASION/ABRASION forming a NOTCH which leads to UNDERCUTTING. The front of the cliff is then unsupported and the weight of saturated clay slides down onto the beach – known a SLUMPING. The sea has to remove this fallen material before it can start eroding the next new section of cliff face – but this doesn’t take more than a few high tides to do Key Terms : Saturated Boulder Clay Lubricated Slip plane Slumping Notch Undercutting Example / Case-Study : Holderness Coast East Yorkshire Tunstall, Aldbrough, South of Mappleton South of Withernsea Possible Questions : What are the different ways in which coasts are eroded? How is erosion of a Soft cliff different from a Hard cliff? Weblinks : http://www.stacey.peak-media.co.uk/holderness/holderness.htm Watch this BBC video clip on Slumping

Coasts : Features of Erosion / ‘Soft’ Coastline erosion – Human consequences 9 The fact that boulder clay is not solid rock – but deposits from the ice-sheets of the last glaciation, means than it is relatively quickly eroded – on average about 2-4 m is eroded each year where there is no coastal protection, but in winters with particularly strong on-shore winds pushing powerful storm waves, it can be up to 12m. The consequences are: Environmental Impact : Loss of agricultural land. Holderness is Grade 2 arable (wheat/barley) land. (2nd best of 5 grades) Economic Impact: Loss of tourist facilities such as caravan sites. Owners have to buy or rent fields further inland and move caravans away from the cliff edges Social Impact : Residents lose gardens and eventually have to move out of their homes. They get no compensation and no-one will buy them. They have to pay to have their homes demolished as they can’t let them collapse onto the beach below. Political Impact : local councillors have to decide if they are going to pay for coastal protection and cliff defences – or let the coast erode with the loss of roads, farms & villages Key Terms : Coastal protection Environmental impact Economic impact Social impact Political impact Example / Case-Study : Holderness Coast East Yorkshire Tunstall, Aldbrough, South of Mappleton South of Withernsea Possible Questions : What are the human consequences of coastal erosion? What arguments are put forward for protecting coasts from erosion? Weblinks http://news.bbc.co.uk/1/hi/england/humber/7103504.stm Watch this BBC video clip on Holderness Watch this BBC video on Happisburgh

Coasts : Processes of Deposition / Transportation of material 10 Waves are the main movers of material eroded from cliffs. As waves break they push material up the beach (SWASH); as they fall back to the sea they drag beach material with them (BACKWASH). Gentle waves have a stronger Swash than Backwash so build up the beach – known as Constructive Waves. Storm waves have a more powerful Backwash than Swash, so remove more material from a beach – known as Destructive Waves. Key Terms : Prevailing wind direction Cliff material / debris Swash Backwash Constructive Destructive waves Storm wave Longshore Drift If waves approach the beach from an angle as a result of the prevailing wind blowing onshore at an angle, the result is LONGSHORE DRIFT. Waves move material up and across the beach (angled Swash), but gravity pulls the backwash straight back to sea at right-angles to the coastline. Over just a few hours this can move material along the coast. Example / Case-Study : Holderness Coast East Yorkshire Beach at Hornsea & Withernsea Possible Questions : How does eroded material get transported along a coastline? How and why does Longshore Drift take place? Weblinks http://www.s-cool.co.uk/gcse/geography/coasts/coastal-transportation-and-deposition.html Watch this BBC video clip on Longshore Drift

Coasts : Processes of Deposition / Transportation of material 11 Benefits of Longshore Drift : Builds up wider beaches at coastal resorts with groynes so more people can use the beach Provides more beach material further along the coast to help protect coastline from erosion Key Terms : Prevailing wind direction Cliff material / debris Swash Backwash Constructive Destructive waves Storm wave Longshore Drift What is the evidence that Longshore Drift is taking place? Waves approach at an angle to the shore Beach material is Higher on the side of the groyne facing the prevailing wind and waves Example / Case-Study : Holderness Coast East Yorkshire Beach at Hornsea & Withernsea Eroded material (chalk pebbles from Flamborough head) are found down the coast where the natural cliff material is Boulder Clay Possible Questions : What is the evidence that Longshore Drift is taking place? Are there any benefits of Longshore Drift? Beach is Wider on the side of the groyne facing the approaching waves Weblinks http://www.yorkshire-east-coast-unofficial-guide.com/withernsea-sands.html

Coasts : Features of Deposition / Spit, bar and tombolo 12 As cliff and beach material is transported along a coast by Longshore Drift, if the flow is interrupted or slowed down, the material is DEPOSITED to form a range of Features of Deposition. A Spit, bar and tombolo are all low-lying beaches made up of sand, gravel, pebbles and rise just a few metres above high tide. Beach grasses may grow in them (marram grass) and the roots then stabilise the features and wind-blown sand may accumulate further. But their low height may mean they are submerged, altered or washed away in severe storms when Erosion is more powerful than Deposition. Key Terms : Longshore Drift Deposition feature Spit Bar Tombolo Peninsula Spit A linear beach that extends from the shore across a river estuary or along the coast – but doesn’t join on to any other feature. It is recurved at its end depending on which is the most powerful current. e.g Spurn Head, E. Yorkshire Bar A Spit which goes right across a bay and joins onto a shore at the other side. Usually where there is no strong river current trying to get to the sea e.g Slapton Ley, Dorset Tombolo A Spit which extends out to join on to an island so that it forms a Peninsula rather than an Island. e.g. Chesil Beach, Dorset Example / Case-Study : Spurn Head, E. Yorkshire (Spit) Slapton Ley, Dorset (Bar) Chesil Beach, Dorset (Tombolo) Possible Questions : Describe and explain the formation of a coastal feature of deposition. What is the difference between a Bar and a Spit? Is this a SPIT TOMBOLA or BAR ? Weblinks http://www.chesilbeach.org/Chesil/index.html Watch this BBC video clip on a Spit

Coasts : Features of Deposition / Spit, bar and tombolo 13 Key Terms : Longshore Drift Deposition feature Spit Bar Tombolo Recurved Lagoon Salt Marsh A SPIT is unable to extend right across an estuary due to the force of the river current finding a route out to the sea. It is RECURVED at the end in the direction of the strongest of the two currents. In Spurn Head’s case, the North Sea current is more powerful than the River Humber current, so the spit curves in towards the estuary. A BAR is a spit which extends across a bay and reaches the shore on the other side. The water which is cut off becomes a salt-water LAGOON of still water. Eventually, over time the lagoon fills in with wind-blown sand, sediment, reeds and other vegetation and becomes a marsh. This is SLAPTON LEY in Dorset. Example / Case-Study : Spurn Head, E. Yorkshire (Spit) Slapton Ley, Dorset (Bar) Chesil Beach, Dorset (Tombolo) Possible Questions : What is the environmental value of a spit, bar or tombolo? Are these permanent or temporary features of coastal deposition? A TOMBOLO – where a spit extends out to an island and joins it to the mainland. The most famous is CHESIL BEACH in Dorset at 11 miles long. Weblinks http://www.field-studies-council.org/slaptonley/

Coasts : Features of Deposition / Evolution of Spurn Head, E Coasts : Features of Deposition / Evolution of Spurn Head, E. Yorkshire – A SPIT 14 A : Sea erodes the coast and Longshore Drift transports material down the coast B : The North Sea and R. Humber currents meet, slow down & deposit their material. The N.Sea current is stronger so the recurved spit bends in to the Humber channel. A C North Sea Current D River Humber Current B E C : As the Spit head grows southwards, erosion still takes place up-coast D : The neck of the spit has more erosion than deposition – so gets thinner E : The sea breaks through the neck, the spit head is an island and is eroded away

Coasts : Features of Deposition / Features of the spit at Spurn Head 15 Direction of the River Humber current Direction of the North Sea current Deposited river silt (mud) Turbulence where 2 currents meet Recent Deposition Thin neck of spit Likely breach Spurn Lighthouse Spurn Lifeboat station

Coasts : Features of Deposition / Issues of coastal protection of a Spit 16 The thin neck of Spurn Head is only a few metres wide. Victorian coastal engineers tried to stop the spit eroding away at its thinnest point over a hundred years ago, but their wooden groynes have now collapsed and are no longer effective. The issue is whether to protect the spit from further erosion, or let the sea carry out its operations, and erode it away. Key Terms : Longshore Drift Deposition feature Spit Estuary Issues if the spit is allowed to be eroded away: The 7 homes of Britain’s only full-time lifeboat crew of the Humber lifeboat are located at the southern end. They would have to be relocated – possible to Grimsby if the spit eroded away – meaning a longer journey time into ships in distress in the N. Sea The Humber pilots are based there too – they go out to ships entering the Humber estuary – one of the busiest in Britain – to guide ships around the shifting and dangerous sand-banks of the estuary. The spit is an important route for migrating birds from the continent which, in spring, use the spit to guide them into Britain, and in autumn on their flights south for the winter. The Spit is managed by the Yorkshire Wildlife Trust and is a vital habitat for many plants & insects Issues if the spit is protected from further erosion The costs of protecting the entire length of the spit would be huge. The Victorian attempts to keep the spit in one position have increased its current problems as the Holderness coast to the north continues to erode westwards – leaving the spit more exposed to NE winds and waves. The erosion of material from the spit provides important material to help protect the beaches south of the Humber in Lincolnshire and even the Netherlands. Stopping the erosion and movement of this material from Spurn would cause faster erosion elsewhere. Example / Case-Study : Spurn Head, E. Yorkshire (Spit) Possible Questions : Why are there disagreements about whether to protect coasts from further erosion? What are the issues surrounding the management of sensitive coastal environments? Weblinks http://www.spurnpoint.com/ http://news.bbc.co.uk/1/hi/england/humber/8439570.stm