Coastal formations

Question 1

Caves, arches and stacks (NOT BEEN IN TEST BEFORE)

Answer 1

1. ) Form at headlands where the rocks are relatively hard or resistant with the sea on three sides.
2. ) As destructive waves break against headland, cracks and joints in the rock are eroded to form a cave through hydraulic action and abrasion.
3. ) Hydraulic action and abrasion break cave making an arch - waves break blocking the entrance to the cave and traps air compressing the cave walls.
4. ) Arch breaks due to gravity leaving a Pinnock of rocks which undercuts and makes a stump.

Question 2

Spit formation

Answer 2

Wave direction determined by prevailing winds resulting in swash and backwash proceeding up the beach.
Sediment moved along the coast by longshore drift in constructive waves.
Where the coast changes direction materials are deposited offshore to form a salt marsh.
Overtime, material builds up off the coast causing a spit

Question 3

Bar formation

Answer 3

A bar is a ridge of sand or shingle across the entrance to a bay or a river mouth where fresh water is trapped behind to form a lagoon.

1. ) Wave direction determined by prevailing winds resulting in swash and backwash up the beach.
2. ) Sediment moved along the coast by longshore drift deposited at a bend in the coastline.
3. ) Deposition continues in a line across the entrance to the bay or river mouth , trapping fresh water behind.

Question 4

Hard engineering technique (pros / cons)

Answer 4

Groynes are wooden structures built along the beach at right angles.

They are quick to construct and interrupt longshore drift.
They trap the sediment and broaden the beach while the beach absorbs the waves energy.

Interruption of the movement of sediment can have impacts further along the coast.
While, rock groynes can be unsightly

Question 5

Soft engineering technique (pros / cons)

Answer 5

Beach nourishment is when sand or shingle is added to a beach to make it higher or wider.

The beach can absorb more wave energy and protect the coastline.
Sediment is obtained locally so blends in, encouraging tourism.

Needs constant maintenance, which can become expensive.
This work is often undertaken inn the summer, disrupting beach users.