Can you coasts? Define Constructive waves Destructive waves Define Erosion Corrasion Attrition Solution Hydraulic action. Long shore drift Deposition Explain the formation of Wave cut platform Caves, arches and stacks Beaches and spits State the difference between hard and soft engineering in tackling coastal erosion. Give examples of soft engineering solutions to tackle erosion Beach nourishment Give examples of hard engineering solutions to tackle erosion Sea walls Gabions Groynes Name a case study of sustainable coastal erosion management in the UK and evaluate its impact. Name: Weaker winds Classify the statement according to whether they would be associated with constructive or destructive waves. Strong winds Swash stronger than Backwash High waves High energy Low energy Deposition greater Short wave length Long wave length Long fetch Short fetch Backwash stronger than Swash Wave frequency: 11-15 per minute. Erosion greater Low waves Wave frequency: 6-9 per minute. Define these terms. Erosion Weathering Corrasion Attrition Hydraulic Action Solution How do the deposits of erosion and weathering differ? Erosion Weathering Using the labels below, draw a fully labelled diagram to show the formation of a wave cut platform. High tide Low tide Between high and low tide rocks are hurled at the base of the cliff- called corrasion. This creates a wave cut notch, the cliff has been undercut. The top of the cliff becomes unstable. This overhang will collapse into sea providing more material for corrosion. The cliff has now retreated. The process of corrasion will continue. Because there can be no erosion below low tide a rock platform is left- called a wave cut platform- this is exposed at low tide. Wave cut platform Illustrate your understanding of the following terms, by drawing diagrams and writing brief explanations for each. Transport Solution Suspension Saltation Traction Deposition Swash and Backwash Long shore Drift Annotate the diagram to illustrate how material is moved along the coastline. Annotate the diagram to illustrate how a coastal spit is formed. Annotate this diagram to explain how a coastal stack forms. Can you define these following terms? Cover the term and try to define it. If you can’t, write it out. THE DYNAMIC LANDSCAPE - COASTS Abrasion / corrasion Attrition Backwash Beach replenishment Constructive wave Corrosion / solution Deposition Destructive wave Differential erosion Erosion Gabion Groynes Hard engineering Hydraulic action Long-shore drift Load Revetements Roll-back Saltation Sea walls A process of erosion – waves hit the coast and throw pebbles against the cliff face. These knock off small parts of the cliff causing undercutting A process of erosion – transported particles hit against one another making the particles smaller and rounder The movement back down the beach of water from a breaking wave, powered by gravity, at right angles to the shore A hard engineering flood / erosion control whereby material is taken from somewhere and dumped on a beach to maintain it. Material often dredged from off-shore A wave with strong SWASH and weak BACKWASH which contributes deposition to a beach The process by which water (river or sea) reacts chemically with soluble minerals in rock (eg chalk and limestone) and dissolves them The dropping of material A wave with a strong BACKWASH and a weak SWASH which erodes a coast Waves will erode hard rock less fast than softer rock, resulting in uneven cliff faces and coastlines (headlands and bays) Wearing away of landscape by action of wind, water, ice Cages of stones on a beach; a hard engineering solution to cliff erosion, designed to absorb wave energy Wooden or concrete walls, built perpendicular to shoreline down the beach, designed to trap material carried by long shore drift and thus maintain a wide beach. A hard engineering solution to cliff erosion and coastal flooding A strategy to control a natural hazard (flooding) involving man made structures A process of erosion – soft rocks are washed away by the sea; air trapped in cracks by the force of water expands as wave slips away. The resulting ‘mini explosion’ weakens the rocks over time, causing cracks to widen and sections of cliff to break away Process whereby beach material moves along a coastline, caused by waves hitting the coast at an angle Material transported by the sea (or a river) Ladder structures built against cliff base. Hard engineering, designed to absorb wave energy and protect cliff from erosion. A version of ‘managed retreat’ where rather than protect the coastline from erosion, installations such as caravan sites (Holderness) are moved further inland The hopping of medium sized load along the sea bed (or river bed) A large, expensive concrete structure, built at the back of a beach, to protect high value land from floods. Usually recurved to direct / or x Soft engineering Solution / corrosion Spit Stack Sub-aerial erosion / weathering Suspension Sustainable Swash Traction Transportation Wave cut notch Weathering waves downwards. A wider base than top gives firmer foundations. They deflect wave energy, and thus tend to undermine their own foundations. Hard engineering. A strategy to control a natural flood / cliff erosion hazard which uses and blends into the environment, thus making it often sustainable The process by which water (river or sea) reacts chemically with soluble minerals in rock (eg chalk and limestone) and dissolves them A tongue of deposited material, stretching out to sea parallel to the coastline and attached to it at one end. Formed due to long shore drift. An isolated pillar of hard rock standing off a headland, surrounded by water. Was once part of the headland. Will eventually erode to form a stump. An erosion feature. Processes of erosion and weathering taking place on cliff tops (eg freeze thaw, rain, wind) Transportation of the smallest load eg fine clays and silts which is held up continuously within a river or seawater A way of using resources so that they are not destroyed but remain available for others to use in the future. Sustainable flood protection should be EFFECTIVE, FAIR, AFFORDABLE and PROTECT THE ENVIRONMENT The movement of a breaking wave up the beach, powered by the momentum of the breaking wave. Direction dictated by prevailing wind / wave direction The rolling of large rocks along a river or sea bed The movement of material across the earth’s surface Area of erosion at base of headland between HTL and LTL. The BREAKDOWN of rocks IN SITU Question- With the aid of a labelled diagram, explain the formation of a wave cut platform. (6) Question- With the aid of a labelled diagram, explain the formation of a coastal stack. (6) Question- With the aid of a labelled diagram, explain the formation of a coastal spit. (6) Answer these questions and return them to your teacher for feedback. Defence Groyne Diagram Hard or soft? Hard Disadvantages Unattractive Prevents access to the beach Health and safety hazard Also provide a flood defence Long-term Some areas of the coast allowed to be eroded or flooded Managed retreat Beach nourishment Advantages Beaches develop Good for tourism Also provide a flood defence Long-term Power of waves reduced Rocks eroded instead of coastline Gabion Sea Wall How it works? Hard Soft Complete the table to help explain how these protection strategies work and their advantages and disadvantages. £100/m £4,000/m Economic loss potential farmland, homes, industry etc. Looks natural Access to beach maintained Relatively cheap Cost £7000 each ? £20/cu.m For an area of coastline you have studied, explain WHY it needs to be protected and HOW this could be done (in a MEDC). Area of coastline = ____________________________ Reasons WHY this area needs to be protected __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ How this area could be protected __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ _______________________________________________ (9) Case study of sustainable coastal management: Holderness Coast. Why is coastal management needed? The coastline is made of soft glacial till called boulder clay. This was deposited in the area during the last glacial advance- 12,000 years ago. There are no wide sandy beaches to protect the cliffs, because the cliffs are made of fine clay. This is transported away or held in suspension. The coast has little protection from waves from the North-East. These have a long-fetch and are powerful. Between Flamborough and Spurn Head an average of two metres of coast is lost each year. Needed to protect important settlements reliant upon the tourist economy and key infrastructure, such as gas terminals. Strategies used. Bridlington has 3.6 km of sea wall and groynes to stabilise the beaches. Bridlington is a popular tourism destination, and has a popular of 34,000. Hornsea has 1.6 km of sea wall, groynes and rock armour. Mappleton was only allowed defences after an economic case was made. There is a road that links many of the coastal villages, this was threatened by the cliff retreat. 450 metres of cliff are protected at Mappleton, using 61,500 tons of rock armour, two groynes and a sloping revetment. Withernsea has 2.3 km of sea wall, groynes and rock armour. A small offshore rock armour defence has also been developed. Major North Sea gas terminals are located to the north of the village of Easington. The Easington defences needed carefully consideration, as there are two Environmentally Sensitive Areas nearby. At Easington a 1km revetment was built along the base of the cliff near the gas terminal, using 133,000 tonnes of rock. To ensure that beach material is not maintained, the defences hug tightly to the cliff at Easington- allowing material to be transported to the ESAs. 10 The local district councils have a roll-back policy when considering new development. This means that existing caravan sites will be closed, and then moved 400 metres from the coast. It is hoped that the policy of roll back will help maintain the local economy. New developments need to justify a coastal location. They must also be 30 to 200 metres from the present coast. How sustainable is the management? Limiting erosion along the Holderness coast would mean less material travelling south to the Humber estuary and coast of Lincolnshire. Nearly 50,000 people live around the Humber estuary. Material from Holderness is deposited on the mudflats and salt marshes of the Humber estuary and the coast of Lincolnshire- protecting the areas from flooding. Most of the land at risk is farmland, this has limited value and makes protection hard to justify. The policy of protection is to defend larger settlements but to do nothing to prevent erosion elsewhere. Preventing erosion along the entire coastline would be highly expensive, hence decision for the roll-back policy. Physical Beach nourishment Biological Chemical Nature of the n deposits Weathering Solution Erosion Attrition Suspension Hard Types Long Shore Drift Deposition features Wave Cut Platform Swash Factors influencing waves Backwash Destructive Definition Flow Slide Solution Transport Constructive Fall Soft Saltation Waves Mass movement Gabion Type Types Erosion features Stack Groyne Protection Corrasion Definition Rock armour Hydraulic action Types Definition Headland Nature of the deposits Sea Wall Slump Bay Spit Estuary ManagementHolderness Causes Strategies- Mappleton Make an A3 copy of this mindmap. Illustrate and annotate it. Sustainable