Geography Quiz on Rivers, Coasts, and Population Settlement
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 –