Transport and Depositions on the Coast

Question 1

What is transportation?

Answer 1

When we are talking about the transportation of materials along the coast, we are talking about how they are moved. There are four ways that waves and tidal currents transport sediment. These can then contribute to the movement of sediment by longshore drift.

Question 2

What are the 4 types of transportation?

Answer 2

Traction

The rocks are dragged and rolled in the water with force of water and keep getting eroded along the way.

Saltation

Small particles like small rocks and pebbles bounce with the force of water and move with it.

Suspension

Small particles are easily suspended in the sea water. Material like clay and silts are suspended and flow away with the flow.

Solution

Some rocks dissolve in the salt water and form a solution.

Question 3

What is longshore drift?

Answer 3

The movement of sediment along the coast parallel to the shoreline and dependent on the wind direction.

The prevailing wind blows waves carrying sediment into the beach at an angle, the waves break on the shore (swash) and as the water runs back (backwash) into the sea it carries the sediment back down the beach, perpendicular to the angle of the shoreline under the influence of gravity. This results in a zigzag motion as sediment is transported along the coastline. This process means that over time beaches can change shape.

Question 4

What is the main use for Groynes?

Answer 4

Groynes can be built to interrupt the flow of longshore drift, but inevitably some sand and gravel can escape.