Coastal Erosion and Deposition

What factors influence wave energy and size?

Duration of wind, strength of wind, and distance traveled by the wave (fetch).

How are waves created?

Waves are created by wind blowing over the surface of the sea, causing friction and energy transfer, resulting in water particle rotation.

Constructive Waves

Waves that have a greater swash than backwash, causing deposition on the coastline.

Destructive Waves

Waves that have a greater backwash than swash, causing erosion along the coastline.

Hydraulic Action

A process where waves crash against cliffs, compressing air in cracks, leading to erosion as the air expands.

Abrasion (Corrasion)

A process where sediment carried by waves scrapes and wears away cliff faces like sandpaper.

Attrition

The process where rock fragments and pebbles carried by waves collide, becoming smaller and smoother over time.

Solution (Corrosion)

A process where seawater slowly dissolves certain types of rock, such as limestone and chalk.

What is Mass Movement?

The downhill movement of weathered material due to gravity, often following wave erosion.

Rockfall

A type of mass movement where pieces of rock break off cliffs, common in steep and weathered areas.

Slides (Landslides)

A type of mass movement where sections of rock or soil move down a slope along a slide plane.

Slumps

A type of mass movement where blocks of material move down a curved slip plane, creating a terrace-like profile.

What is Longshore Drift?

A process of sediment transportation along the coast caused by the zig-zag movement of swash and backwash.

Swash

The movement of waves up the beach at an angle, carrying material with the direction of the prevailing wind.

Backwash

The movement of water returning down the beach straight back due to gravity, perpendicular to the shoreline.