Coastal Processes and Features Flashcards
What is the dynamic (ever changing) nature of the coast due to?
The action of constructive and destructive waves.
Define coastal erosion
The process of wearing away rock along the coast
Define corrasion
Where particles carried by the waves crash against the cliffs, eroding them
Define attrition
Where particles carried in the waves crash into each other, becoming smaller and smoother.
Define corrosion
Where salt in the seawater slowly dissolves the cliffs.
The material produced by corrosion is carried away by what process?
Solution
Define hydraulic pressure
Where water traps air in cracks in the rock. This air is compressed by the waves which pressurises the rocks, causing them to eventually crack.
Define longshore drift.
The overall process of coastal transportation, where waves approach the beach at an angle in the swash and come down straight in the backwash, carrying material along the coast in a zig-zag movement.
State why waves can approach the coast at angle.
Due to the direction of the prevailing wind
Describe the process of longshore drift. [3]
- The swash of the waves carries material up the beach at an angle due to the direction of the prevailing wind.
- The backwash then flows it back to the sea in a straight line at 90 degrees because of gravity.
- This zig-zag movement of the waves carries material along the beach.
Describe the effects of constructive waves. [3]
Constructive waves:
- Cause deposition which builds up the coast
- Push sand and pebbles up the beach
- Have a strong swash and weak backwash.
Describe the effects of destructive waves. [3]
Destructive waves:
- Erode the coast
- Drag sand and pebbles out to sea
- Have a stronger backwash than swash.
Describe the size of constructive waves.
Low and far apart.
Describe the size of destructive waves.
High and close together.
Describe the frequency of constructive waves.
Less frequent than destructive waves, about 6 to 9 a minute.
