Coasts

Question 1

What is attrition

Answer 1

Rocks knock against each other wearing each other away

Question 2

What is abrasion

Answer 2

Fragments of rock being picked up and hurled by the sea at a cliff

Question 3

4 types of transportation

Answer 3

Solution, traction, suspension, saltation

Question 4

What is traction

Answer 4

Rocks rolling along sea bed

Question 5

What is saltation

Answer 5

Rocks bounced along sea bed

Question 6

Types of mass movement

Answer 6

Rock fall , mud flow , slumping , landslide

Question 7

Factors that determine wave size

Answer 7

Strength of wind
Fetch
Length of time the wind blows

Question 8

Differences between constructive and destructive waves

Answer 8

Constructive = low energy, slash stronger than backwash, deposition greater
Destructive = high energy, backwash stronger than swash, erosion greater

Question 9

3 types of weathering with examples

Answer 9

Biological = animals burrowing in rocks
Physical / mechanical = freeze thaw, water freezing in cracks in rocks then melts and breaks rock
Chemical= oxidation, oxygen breaking down rocks over time

Question 10

What is concordant coastlines

Answer 10

Have the same type of rock along its length
Tend to have fewer bays and headlands
Such as lulworth cove

Question 11

What is discordant coastlines

Answer 11

Where the rock alternates bands between hard and soft rock

Question 12

What is a tombolo

Answer 12

Ridge of sand or shingle connecting an island to mainland

Question 13

What is a bar

Answer 13

Where a spit extends fully across a bay and connects two pieces of land together
Form a lagoon behind it

Question 14

What is example of soft rock

Answer 14

Clay and sand

Question 15

Example of soft rock

Answer 15

Clay and sand

Question 16

Example of hard rock

Answer 16

Chalk

Question 17

What is rockfall (mass movement)

Answer 17

When the cliff materials break and crumble down the cliff

Question 18

What are landslides (mass movement)

Answer 18

Large blocks of rock slide downhill

Question 19

What are mudflows (mass movement)

Answer 19

Saturated soil (soil filled with water) flows down a slope.

Question 20

What is slumping (mass movement )

Answer 20

Large area of land moving down the slope, it leaves behind a curved indented surface

Question 21

Formation of bar and spit (4 marks)

Answer 21

Longshore drift follows the direction of the prevailing wind. It usually hits the coast at an oblique angle. The swash carries material up the beach in the same direction as the waves. The backwash then carries material down the beach at a right angle back towards the sea. Over time, material zig zags along the coast. Spits form at a sharp bend in the coastline. Spits form when the coastline suddenly changes shape, sand starts to build up in the sheltered side of the headland . A spit will continue to grow until the water becomes too deep or until material is removed faster than it is deposited. Wave refraction carries material round into more sheltered water which forms a hook. Can form a salt marsh behind it. Longshore drift may cause a spit to grow across a bay causing a lagoon to form behind it. This feature is called a bar.

Question 22

Advantages and disadvantages of rock armour (rip rap)

Answer 22

A= disperses the energy of the waves and reduces their erosional power. Structure is quick to build and easy to maintain. Much cheaper than a seal wall. If well maintained it can last a long time. It is versatile as it can be placed in front of sea wall to lengthen its lifespan or used to stabilise slopes on sand dunes. Often used for fishing.
D=access ri beach is difficult as people have to climb over rock armour. Cost may be high especially when it has to be imported. Can look unattractive

Question 23

Advantages and disadvantages of groynes

Answer 23

A=designed to stop material moving along the beach by Longshore drift they work by building up amount of sand on the updraft side. They create wider beaches with is popular for tourists and boost local economy. Reduces risk of damage making residents and local businesses fell more secure. Not too expensive. If well maintained can last up to 40 years
D= beaches downdrift are starved of beach material due to their impact on Longshore drift this leads to increased erosion which has economic impact further along coats. Need regular maintenance as they can rot.

Question 24

Advantages and disadvantages of sea walls

Answer 24

A= effective in protecting cliffs from erosion and also act as a barrier to prevent flooding, deflect wave energy back to sea, give people sense of security. Often have a promenade of too which doubles up as a cycle route -could attract tourists. If well maintained could last for years. Do not impede the movement of sediment downdrift so do not disadvantage other areas
D= very expensive to construct and maintain (over 5000 pound per metre), recurved sea walls can increase the erosion of beach material and may destroy habitats

Question 25

What is hydraulic action

Answer 25

Power of the waves as they smash onto a cliff. Trapped air is forced into holes and cracks in the rock, eventually causing the rock to break apart

Question 26

How is a wave cut platform formed

Answer 26

Waves cause most erosion at the foot of a cliff, this erosion forms a wave cut notch which is enlarged as erosion continues. The rock above the notch becomes unstable, and eventually collapses. The collapsed material is washed away and a new wave cut notch starts to form. Repeated collapsing results in the cliff retreating. A wave cut platform is the surface that’s left behind as the cliff retreats. Pebbles grind over the rocky platform often causing it to become smooth. IF NEEDED TO DRAW DIAGRAM LABEL: HIGH TIDE, LOW TIDE LEVEL, RETREATING COASTLINE, PREVIOUS POSITION OF CLIFF, CURRENT POSITION OF CLIFF

Question 27

Advantages and disadvantages of gabions

Answer 27

A= cheap to produce and flexible in final design, can improve drainage of cliffs, will eventually become vegetated and merge into landscape, much cheaper than other hard engineering strategies, last 20-25 years D= wire basket may be subject to heavy wear and tear by abrasion or could rust, hard to install require large equipment, eye sore so can put of toustists visiting pretty heach

Question 28

Advantages and disadvantages of beach nourishment (adding of sediment to beach)

Answer 28

A= usually looks natural and can improve attractiveness of coast so increased tourism, relatively cheap, easy to maintain D= requires constant maintenance to replace beach material as it is washed away. People may be prevented from using beach for several weeks during maintenance. Costs up to 500,000 per 100 meters

Question 29

What is dune regeneration

Answer 29

artificial creation of new dunes of restoring existing dunes using strategies such as marram grass or fencing them off from humans

Question 30

Advantages and disadvantages of dune regeneration

Answer 30

A= sand dunes act as a physical barrier between the sea and the land, they absorb wave energy and in doing so protects the land from the sea, increase biodiversity providing a greater range of natural habitats for plants and animals. D= can be easily damaged by storms and it can time consuming to plant the grass and maintain the area and can also deter tourists. Costs 400-2000 per 100 metres

Question 31

Formation of headland and bays (4 or 6 marks)

Answer 31

Formation of head lands and bays changes over time due to differences in resistance of rocks to erosion, some parts of coast may retreat faster than others. Discordant coastline is when it is alternated bands of soft and hard rock. The soft less resistant rock will be eroded quicker than the harder more resistant rock and differences become more pronounced. Eventually there will be headlands that stick out into the sea and bays where the land has been worn back. The headlands are more exposed to wave attack and erosional landforms develop. Due to wave refraction the energy of the waves is focused on the headlands and spread out into the bays.