Geography The Coastal Zone

Constructive

Gentle Beach

Wave Crests Far Apart

Bad For Surfing

Weak Backwash

Strong Swash

Low WAves

6-8 Every Minute

Destructive

Steep Beaches

Wave Crests Close

Good For Surfing

Weak Swash

High Waves

15 Waves A Minute

Strong Backwash

Processes

Marine Processes

Hydraulic Action

Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.

Attrition

Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.

Corrosion/Solution

Acids contained in sea water will dissolve some types of rock such as chalk or limestone.

Abrasion/Saltation

Bits of rock and sand in waves grind down cliff surfaces like sandpaper.

Sub-aerial Processes

Chemical Weathering

Freeze-thaw

Weathering

Human Activity

Biological Weathering

Geology

Permable

Subtopic

Imperable

Features

Headlands

Bays

Wave-Cut Notches

Wave-Cut Platforms

Cracks

Cave

Arch

Stack

Stump

Cliffs

Lonshore Drift

The direction of prevailling wind causes the swash of the waves to carry material up the beach at an angle. The backwash then flows back to the sea in a straight line at 90°.
Continual swash and backwash transports material sideways along the coast.

Suspension

Small particles are carried in water, eg silts and clays, which can make the water look cloudy. Currents pick up large amounts of sediment in suspension during a storm, when strong winds generate high energy waves.

Solution

Minerals are dissolved in sea water and carried in solution. The load is not visible. Load can come from cliffs made from chalk or limestone, and calcium carbonate is carried along in solution.

Traction

Pebbles and larger sediment are rolled along the sea bed.

Saltation

Load is bounced along the sea bed, eg small pieces of shingle or large sand grains. Currents cannot keep the larger and heavier sediment afloat for long periods.

Hard Engineering

Rip Rap

Sea Wall

Offshore breakwater

Groynes

Revetement

Soft Engineering

Beach Building

Gabions

Bastions

Mappleton

Old Harry And Wife

Subtopic

Fetch

The distance the wind blows over

Swash

The water rushing up the beach

Backwash

The water drains back down the beach

Deposition

When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying. This Process happens when the swash is stronger than the backwash and is associated with constructive waves

Beaches

Spits

Salt Marshes

Bar

Tombolo