Coasts Exam Questions Flashcards
Explain the formation and breaking of waves (6 marks)
Wind blows across the sea creating ripples. Friction between the surface and the wind is transferred into energy and circulates under the wave. How big the wave is depends on the velocity (strength) of the wave, time it takes to blow across the sea and the fetch (distance of the queen sea, over which the wind blows). As the shallowness of the ocean floor increases the circulation turns into an elliptical, oval shape and the wave rises.the wave eventually breaks and rushes up the shore this is called the swash. Then finally the backwash rushes back into the ocean and resumes this process.
How does sediment move along the coastline in 4 steps (4 marks)
1) prevailing wind blows in at an angle towards the coastline.
2) this creates waves that swash up the beach diagonally + carry sediment
3) the backwash returns directly down the beach (right angle) moving sediment
4) this process repeats many times causing the sediment to move in a zig zag motion, this is called longshore drift
Coastal management schemes are effective in protecting the coastline from physical processes
Do you aggree? Using an example you have studied, explain your answer.
East Bourne built several coastal management stratgies these include ; sea wall, greyness, rip rap , beach nourishment. I believe the most effective stratgies was sea wall. It helped to protect the town Eastbourne from physical processes such as hydraulic action, which is where water from the waves crash towards the cliffs forcing it way through the crack. The air pressure Im between the water and inside of the cliff eventually gives way. The sea wall prevents the waves attacking the cliff and instead the waves erode the sea wall. Another stratgies that wasn’t as effective is beach nourishment. This was less effective because every year a storm came and eroded 1 million tons of shingle used on beac, leading to expensive replacement of the sand every year. Sand was also transported via longshore drift which had then been prevented using 94 ekki wood groynes. Overall i think that coastal management strategies where effective because even if the problem isn’t permanently solved it keeps the homes in the villages safe from the threats in the meantime.
