Waves and Erosion
What are the two types of waves?
Destructive and constructive waves.
How is sediment transported across a beach?
Long-shore drift.
a. Broken down b. Transported c. Dropped
C. Dropped
Name one coastal landform of erosion.
Headlands and bays.
What are 2 categories of coastal management
Hard and soft engineering
What is one difference between constructive and destructive waves?
Constructive: Low energy, low frequency, short fetch, strong swash, flat and low, deposition.
Destructive: High energy, high frequency, long fetch, strong backwash, tall and high, erosion.
What is swash?
When waves move up a beach.
Name two reasons sediment would be deposited.
Sheltered area, low energy waves, water is shallow.
Name one landform of coastal deposition.
Spit
Name two types of hard engineering
Groynes, sea walls, Gabions, rock armour
Name four processes of erosion.
Hydraulic action, abrasion, attrition, solution, compressed air.
What is backwash?
When waves move down a beach.
Sea wall, gabion, groynes, rock armour.
How does a headland and bay form?
Alternating bands of hard and soft rock. The soft rock erodes more rapidly than the hard rock. The part that juts out is the headland and the part that retreats inland is the bay. Most energy is concentrated on the headlands causing them to erode faster.
Name the benefits of soft engineering
Environmentally friendly, not permanent, slows coastal erosion
Explain hydraulic action.
When the force of the waves erodes the coast as they crash against it.
What pattern does longshore drift have?
Zig zag.
How do sea walls work?
Reflect waves back into sea, slowing erosion.
Definition of a sand spit
Stretch of sand or shingle that extends from the mainland out to sea.
What is beach nourishment?
Taking sand from offshore to add to beaches
Explain Abrasion.
When eroded material (load) in the waves crashes against the coastline.
Explain longshore drift.
Waves move up the beach at an angle, carrying sediment (swash). The waves then move back down the beach (backwash) in a straight line. This zig zag pattern is repeated and transports sediment across the beach.
What is a positive of sea walls?
Slow down erosion.
What is one negative of sea walls?
Very expensive.
What are Groynes?
Cement or wooden walls that run at right angles to the shore