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Objectives. By the end of this lesson you should be able to: explain the difference between swash, backwash and longshore drift list and explain the formation of landforms created by deposition. Coastal deposition. How does the sea create depositional features?. Swash and backwash.
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Objectives By the end of this lesson you should be able to: • explain the difference between swash, backwash and longshore drift • list and explain the formation of landforms created by deposition
Coastaldeposition How does the sea create depositional features?
Swash and backwash • How does the sea create depositional features? • The movement of waves up the beach is known as swash. The movement of water back into the sea is known as backwash. • The swash is responsible for washing material up onto the shore and depositing it there.
What have waves got to do with deposition ? • Waves usually approach the coastline at an angle. • This causes the swash to run up the beach at an angle. • The backwash will return at right angles to the swash, under the influence of gravity.
What is Longshore drift? • Have you ever thrown a ball or stick into the sea, only for it to wash up a few metres further down the beach? • This is because the swash and backwash are moving at different angles to each other. • The swash moves material up the beach at a certain angle, and the backwash pulls it back into the sea at a different angle. • material is moved along the coastline. • This movement of material along the coastline is known as longshore drift.