Transcript of "Coasts Lesson 4 (Depositional Features)"
Coasts Depositional Features Aim: To be able to recognise some features of coastal deposition.
Longshore Drift in action Click on picture for a short video on how longshore drift occurs 2.06
Sand and pebble beach with groynes showing how sand has built up against one side of the groyne. Direction of drift
1. Beach material almost always moves along the beach in a particular direction which is determined by the prevailing winds . 2. If the winds blow the waves parallel to the shore, sand and pebbles are washed up and back down the beach. 3. If, however, the wind blows so that waves come in at a sharp angle to the coast, the swash carries the pebbles at an angle up the beach. 4. When the backwash moves by gravity back down the beach, the pebbles end up at a different position. 5. This process is repeated and pebbles gradually shift along the beach, a process called longshore drift .