What is a constructive wave? (1)
These are long waves with little energy, better at depositing material on the beach. Swash is greater than backwash.
What is a destructive wave? (1)
Shorter waves with lots of energy, drags sediment down the beach. Stronger backwash than swash.
Explain the formation of a stump (6)
Hydraulic action and abrasion erode the headland creating an undercutting of cliff base, which then forms a wave cut notch. An overhang is created as the wave cut notch depends and the overhang cannot be supported so it collapses and the headland retreats. This leaves a rocky platform in from = wave cut platform. The erosion of hydraulic action and abrasion occurs along faults which then produces a cave. The cave emerges either side to produce an arch. With continued erosion the arch widens and it cannot be supported the roof collapses forming a stack. More erosion undercuts the stack forming a stump as it collapses.
Describe the method of coastal protection shown (2) [picture of rock armour] Large rocks placed at the bottom of the cliff to absorb the wave energy, they are effective at dispersing the wave’s energy.
Suggest how rock armour will protect the housing built along the coast (3) These are large rocks which are placed at the bottom of the cliff. The rocks are randomly arranged and can absorb the waves energy which prevents undercutting of the cliff so less erosion and less collapse. Therefore the cliff won’t retreat back.
Explain the formation of a wave-cut platform (6)
The wave cuts a wave cut notch in the headland as it exploits a point of weakness. The force of gravity and weight of the rock causes it to collapse. Process starts again. After a series of cliff collapses a wave cut platform is left which is exposed during low tide. Describe one method of a coastal protection (2)
Sea Wall – These are hard concrete walls which are built to reflect wave attack on the coast preventing erosion from the land behind – often very expensive and ugly.
Explain how some coastal defences work (4)
Gabions – Metal cages containing pebbles and cobbles placed at the bottom of the cliff. They are used to absorb the wave’s energy and dissipate wave energy shielding the cliff from the erosion. It also lets the water percolate out from the cliff face, reducing the risk of landslide and mudflow. Revetments – These are sloping, slatted, timber walls set at about 45*. They are made from hard woods and the slats in them means water is partly reflected but partly dissipated + some of the water percolates between the slats. They stop undercutting and collapse of the cliff.
Explain how and why cliff collapse occurs in some coastal locations. (4) Hydraulic action and abrasion erode the headlands back. Often in areas of dense jointing lies a fault which is vulnerable to erosion from the waves. Wave cut notch + platforms are often created sometimes forming stacks and stumps.
With the aid of a diagram, explain what happens in long shore drift? (6) The prevailing wind (where the wind usually blows from) causes waves to approach the coast at an angle. Therefore the waves carry the sediment up the beach at the same angle, (45* normally). The backwash however carries the sediment back down the beach at 90* to the beach. It is a zigzag motion which as it is repeated will carry sediment up the beach.
For a holiday resort you have studied, describe some of the solutions to problems caused by tourism. (4)
In Tynemouth, Tyne and Wear; overcrowding, cleanliness, maintaining the appeal and competition of beaches were the problems they faced. The local council improved road signs around the sea front to reduce bottlenecks. One way system was put in place to reduce the risk of hold up on narrow roads. The uninviting walkway from the Metro Station was cleaned and better sign posted. Special, cheap, day tickets are offered on bank holidays to encourage visitors to the beach by...
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