Longshore Drift

Question 1

What is longshore drift?

Answer 1

The movement of sediment along the coast.

Question 2

When does longshore drift happen?

Answer 2

When waves move towards the beach at 45 degree angles and the swash carries sediment up the beach. The wave leaves at a 90 degree angle, pulling sediment back down the beach. This is due to the pull of gravity. This will repeat in a zig-zag motion along the beach, i.e. in the direction of the prevailing wind.

Question 3

When is deposition likely to occur?

Answer 3

When:

• Waves enter an area of shallow water
• Waves enter a sheltered area, e.g. cove or bay
• There is little wind
• No good supply of sediment

Question 4

Draw a diagram of longshore drift.