Learning objectives To explain how beach material is transported along the coastline through the process of longshore drift To describe how deposition creates coastal landforms beaches ID: 1022971
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1. Starter: Unscramble the key words
2. Learning objectivesTo explain how beach material is transported along the coastline through the process of longshore drift. To describe how deposition creates coastal landforms: beaches, spits and bars.
3. The 2 types of waveConstructiveDestructiveFetchPrevailing windsFactors that determine the size of wavesCoasts so far…
4. For example: landslides (Holbeck Hall), rockfalls, mudflows and rotational slipsWeatheringFreeze-thaw (mechanical) and solution (chemical)Non-sea processes that shape the coastlineMass Movement: The downhill movement of material under gravity
5. The 4 coastal erosion processes:Hydraulic actionAbrasionSolutionAttritionCoastal erosion landforms 1:Coastal erosion landforms 2:Wave-cut notches and wave-cut platformsCoastal erosion landforms 3: Headlands and baysCoastal erosion processes
6. The sea uses the same 4 processes to move its load as a river does...TractionSaltationSuspensionSolutionCoastal transportation is the movement of material along a coastlineWhere waves approach the shore ‘head-on’ sediment is moved only up and down the beach, not along it.Coastal transportation
7. Where waves approach the shore ‘at an angle’ sediment will be moved along the beach. Coastal transportation along the shore only occurs where the waves approach the shore at an angle
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9. The transport of sediment along a stretch of coastline caused by waves approaching the beach at an angle. Direction of movementswashBackwashBackwash is always at right angles to the beachLongshore Drift (also known as LSD)Activity: Complete the worksheet
10. Covehithe, SuffolkLSD is in full operation on the Suffolk coast.What problems could LSD create along the stretch of coastline pictured above?How could these problems be solved?
11. Direction of Longshore driftA sandy beach is crucial to tourism in Southwold – the town cannot afford LSD to transport it away.Wooden groynes are used to trap the sand.
12. What evidence is there from the two pictures that Longshore drift is occurring at site A and B? In which direction do you think LSD is operating in both pictures A and B?ABNorthNorth
13. GroynesSediment accumulation due to Longshore DriftWaves approach beach at an angle
14. Trapping sediment in one place through the use of groynes can cause problems further along a coastline. Material is not transported and deposited, so more erosion occurs. Beaches are lost and it can accelerate cliff erosion.
15. How do constructive waves create beaches?Deposition! Waves run out of energy or they break in a sheltered bay. Backwash is weak and pebbles/sand is left behind.Sand dunes are formed by strong coastal winds blowing inland. The dunes are stabilised by the coarse ‘marram’ grass. Coastal deposition landform 1: beaches
16. By transporting material and then depositing it (when the sea loses energy) several different coastal landforms are created – called coastal depositional landforms.
17. Recurved endSalt marshSpit (sand/shingle)Direction of LSDBlakeney Spit, North Norfolk
18. Coastal depositional landform 2: SpitActivity using page 147:Either, draw and label a diagram to show how a spit is formedOr…Read and summarise the information and explain how a spit is formed.You should include the following key words:Longshore driftSalt marshesPrevailing windsEstuary or river mouth
19. If a spit joins one part of the mainland to another it is called a bar.Behind the bar is trapped a freshwater lake or lagoon.Coastal depositional landform 3: BarsActivity: Outline the main differences between a spit and a bar.
20. How much do you know about coasts?