Coastal landscapes

Deposition

Deposition

When waves carrying sediment loose energy and slow down

Mechanical weathering

Breakdown of rock without changing its chemical composition. e.g; freeze thaw weathering.

Chemical weathering

Breakdown of rock by changing its chemical composition. eg; carbonation

Storm surges

When temporary sea level rises becuase strong winds push water onshore

Destructive waves

When waves erode the coast

Constructive waves

When waves deposit material

Hydraulic Power

Waves crash again rock and compress air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and causes bits of rock to break off.

Abrasion

Eroded particles in the water scrape and rub against rock, removing small pieces.

Attrition

Eroded particles in the water collide, break into smaller pieces and become more rounded.

Traction

Large particles like boulders are pushed along the sea bed by the force of water

Suspension

Small particles like silt and clay are carried along in the water

Saltation

Pebble sized particles are bounced along the sea bed by the force of water

Solution

Soluble materials like limestone dissolve in the water and are carried along

Hard engineering

Man made structures built to control the flow of the sea and reduce flooding and erosion

Soft engineering

Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion.

Sea wall

A wall made out of hard material like concrete that reflects waves back to sea

Benefits of a sea wall

Prevents erosion of the coast and acts a barrier to prevent flooding

Disadvantages of a sea wall

It creates a strong back wash that erodes under the wall and expensive to maintain

Gabions

A wall of wire cages filled with rocks, usually built at the foot of cliffs

Advantages of Gabions

Absorb wave energy, reducing erosion. They’re cheap and easy to build.

Disadvantages of Gabions

They’re ugly to look at and wire cages erode over time

Rock armour

Boulders that are piled up along the coast

Disadvantages of rock armour

Absorbs wave energy, reducing erosion and flooding and a cheap defence.

Groynes

Wooden or stone fences that are built at right angles to the coast. They trap material transported by longshore drift.

Advantages of groynes

They create wider beaches which slow the waves. This gives greater protection from flooding and erosion and fairly cheap.

Disadvantages of groynes

They starve beaches further down the coast of sand making them narrower. Narrow beaches don’t protect them well leading to greater erosion

Beach nourishment and reprofiling

Sand and shingle from the sea bed or lower down the beach added to upper part of the beach

Beach nourishment and reprofiling advantages

It creates wider beaches which slow down the waves. This gives greater protection from erosion and flooding

Beach nourishment and reprofiling disadvantages

Taking material from the sea bed can kill organisms like sponges or corals. it’s very expensive and has to be repeated to maintained

Dune regeneration

Creating or restoring sand dunes through nourishment or planting vegetation to stabilise the sand

Dune regeneration advantages

Creates a barrier between land and sea and absorbs wave energy preventing flooding and erosion and stabilisation cheap

Dune regeneration disadvantages

This protection is limited to a small area and nourishment is expensive