Coasts

Question 1

Mechanical weathering

Answer 1

breakdown of rock without changing its chemical composition

Question 2

Salt weathering

Answer 2

main type of weathering that affects coasts

1) sea water gets into cracks in the rock
2) when the water evaporates - salt crystals form
as the crystals form they expand - puts pressure on the rocks
2) repeated evaporation of saltwater and the forming of salt crystals widens cracks and causes rock to break up

Question 3

Chemical weathering

Answer 3

breakdown of rock by changing its chemical composition

Question 4

Carbonation weathering

Answer 4

type of chemical weathering that happens in warm and wet conditions

1) seawater and rainwater have carbon dioxide dissolved in them - makes them weak carbonic acids
2) carbonic acid reacts with rock that contains calcium carbonate such as Carboniferous limestone - so rocks are dissolved by rainwater

Question 5

Biological weathering

Answer 5

breakdown of rocks by living things

plant roots break down rocks by growing into cracks on their surface and pushing them apart

Question 6

Mass movement

Answer 6

shifting of rocks and loose material down a slope e.g. a cliff

happens when the force of gravity acting on a slope is greater than the force supporting it
causes coasts to retreat rapidly
more likely to happen when the material is full of water - acts as lubricant and makes material heavier

Question 7

3 processes of erosion

Answer 7

Hydraulic power
Abrasion
Attrition

Question 8

Hydraulic power

Answer 8

waves crash against rock and compress the air in the cracks
this puts pressure on the rocks
repeated compression widens the cracks and makes rock break off

Question 9

Abrasion

Answer 9

eroded particles in the water scrape and rub against rock - removing small pieces

Question 10

Attrition

Answer 10

eroded particles in the water smash into each other and break into smaller fragments
their edges also get rounded off as they rub together

Question 11

More resistant rocks

Answer 11

Hard rocks like limestone and chalk are more resistant

takes longer for them to be eroded and weathered by physical processes

Question 12

Less resistant rocks

Answer 12

Softer rocks like clay and sandstone are less resistant

eroded and weathered more quickly

Question 13

Joints and faults

Answer 13

cracks and weaknesses in the rock

rocks with lots of joints and faults erode faster

Question 14

Discordant coastlines

Answer 14

coastlines made up of alternating bands of hard and soft rock that are at a right angle to the coast

Question 15

Concordant coastlines

Answer 15

coastlines that are made up of alternating bands of hard and soft rock that are parallel to the coast

Question 16

erosional land forms like bays and headlands are more common on…

Answer 16

Discordant coastlines

because bands of rock are being eroded at different rates

Question 17

Fewer erosional land forms occur on…

Answer 17

Concordant coastlines

because they are eroded at the same rate along the coast

Question 18

What increases the rate of salt weathering?

Answer 18

Warmer temperatures - water evaporates more quickly

Question 19

Impact of storms on UK coastlines

Answer 19

Storms are very frequent in many parts of the UK especially in winter
strong winds create high energy destructive waves which increase erosion of the cliffs
intense rainfall can cause cliffs to become saturated - makes mass movement more likely

Question 20

What are the prevailing winds in the UK?

Answer 20

Warm south westerlies - bring storm from the Atlantic Ocean

south coast is exposed to these

Question 21

Destructive waves

Answer 21

1) waves that carry out erosional processes
2) high, steep, have high frequency (10-14 waves per minute)
3) backwash is more powerful than swash - so material is removed from the coast
4) storms increase the erosional power of destructive waves - can lead to increased rates of coastal retreat

Question 22

Backwash

Answer 22

the movement of the water back down the beach

Question 23

Swash

Answer 23

the movement of the water up the beach

Question 24

How does a wave-cut notch form?

Answer 24

Waves cause erosion at the foot of the cliff through abrasion and hydraulic action which causes a wave-cut notch to form as the cliff is undercut

Question 25

how does a wave-cut platform form?

Answer 25

once a wave-cut notch is formed the rocks above the notch becomes unstable and eventually collapses repeated collapsing results in the cliff retreating a wave-cut platform is the platform that's left behind as the cliff retreats

Question 26

How are Headlands and Bays formed?

Answer 26

1) Headlands and bays form where there are alternating bands of resistant and less resistant rock along a coast - discordant coastline 2) less resistant rock - eroded quickly and this forms bays bays have gentle slopes 3) resistant rock - eroded more slowly and its left jutting out forming a headland headlands have steep sides

Question 27

How does a cave form?

Answer 27

waves crash into the headlands and enlarge the cracks - mainly by hydraulic power and abrasion repeated erosion and enlargement of the cracks causes a cave to form

Question 28

How does an arch form?

Answer 28

``` continued erosion (hydraulic power and abrasion) deepens the cave until it breaks through the headland which forms an arch such as Durdle Door in Dorset ```

Question 29

How does a stack form?

Answer 29

Continual erosion wears away rock supporting an arch until it eventually collapses Further weathering and erosion leaves smaller flatter versions of stacks called stumps

Question 30

Longshore drift

Answer 30

1) waves follow the direction of the prevailing winds 2) they usually hit the coast at an oblique angle 3) swash carries material up the beach in the same direction as the wave 4) backwash then carries material down the beach at right angles back towards the sea 5) over time material zigzags along the coast

Question 31

Constructive waves

Answer 31

waves that deposit more material than they erode low, long, have low frequency (6-8 waves per minute) swash is powerful and carries material up the coast backwash is weaker and doesn't take a lot of material backdown the coast deposit material such as sand and shingle along coast to form beaches

Question 32

Deposition

Answer 32

when material being carries by seawater is dropped on the coast occurs when water carrying sediment slows down so it isn't moving fast enough to carry so much sediment

Question 33

Spits

Answer 33

form a sharp bend in the coastline longshore drift transports sand and shingle past the bend and deposits it in the sea strong winds and waves can curve the ends of the spit - recurved end sheltered area behind the spit is protected from waves - material accumulates in this area so plants can grow over time sheltered area can become - mud flat, salt marsh

Question 34

Bars

Answer 34

formed when spit joins two headlands together the bar cuts off the bay between the headlands from the sea means lagoon can form behind the bar

Question 35

Why is agricultural land often left unprotected?

Answer 35

has low economic value

Question 36

How does farming affect stability of cliffs?

Answer 36

Vegetation helps to bind the soil together and stabilise clifftops clearing vegetation from grazing land to make room for crops can expose the soil and underlying rock - vulnerable to weathering by rain and wind

Question 37

Effects of draining Marshland

Answer 37

reclaimed and drained for agricultural use | reduces the natural flood barrier that marshland provides

Question 38

Positive effect of development on coastline

Answer 38

coasts with lots of settlement may have more coastal defences - people want ti protect their homes/businesses land is better protected against erosion

Question 39

Negative effect of development on coastline

Answer 39

change in the transportation and deposition of material along the coast building on coastal lowlands - restricts sediment supply to beaches which makes them narrower narrower beaches don't protect the coast as well - land is more venerable to erosion

Question 40

Effects of coastal quarries

Answer 40

exposed large areas of rock making them more venerable to chemical weathering and erosion

Question 41

Effect of construction industry on the coast

Answer 41

gravel is extracted from beaches for use in construction industry - for making concrete removed material from coast and increased rick of erosion. as there is less material to protect cliffs

Question 42

Industrial growth at ports has led to increased pressure to build on salt marshes why is this and what is the effect of this?

Answer 42

salt marshes provide flat land and sheltered water - ideal for ports and industry but also natural flood barriers building on them makes lands more vulnerable to erosion

Question 43

What 2 things are making coastal flooding more likely?

Answer 43

Rising sea levels | Increased frequency of storm

Question 44

Rising sea levels

Answer 44

1) pose a threat to low-lying and coastal areas 2) causes higher tides - flood coastal areas more frequently 3) higher tides could also remove larger amounts of material from beaches - lead to increase erosion of cliff as there is less material to protect them from the sea 4) expose more of the coastline to erosion - beaches become narrower as the sea will be able to move further inland

Question 45

Storm frequency

Answer 45

1) climate change is causing storms to be more frequent 2) storms gives the sea more erosional power - hard rock areas - more vulnerable to erosion soft rock areas - erode more quickly 3) sea will have more energy to transport materials - high energy waves can't move material greater distances - leads to some areas with lack of material these areas are vulnerable to erosion and flooding

Question 46

Threats of coastal flooding to people

Answer 46

1) low-lying coastal areas could become permanently flooded - impossible to inhabit 2) coastal industries may shut - damage to equipment and buildings 3) risk of damage to infrastructure 4) fewer tourists - businesses relying on tourism may close leading to loss of livelihood

Question 47

Threats of coastal flooding to the environment

Answer 47

1) damage to ecosystems sea water has high salt content - increased salt levels due to coastal flooding can damage or kill organisms in an ecosystem can also affect agricultural land - reduces soil fertility 2) force of floodwater can uproot trees and plants and standing floodwater drowns trees and plants

Question 48

Hard engineering

Answer 48

man-made structures built to control the flow of the sea and reduce flooding and erosion examples of hard engineering defences: sea walls, groynes

Question 49

Soft engineering

Answer 49

Schemes set up using knowledge of the sea and its process to reduce the effects of flooding and erosion examples of soft engineering defences: Beach replenishment, slope stabilisation

Question 50

Sea walls

Answer 50

a wall made out of land material like concrete that reflects waves back to sea benefits - prevents erosion of the coast and acts as a barrier to prevent flooding costs - creates strong backwash which erodes under the wall and is expensive to build and maintain

Question 51

Groynes

Answer 51

wooden or stone fences that are built at right angles to the coast they trap material transported by longshore drift benefits - create wider beaches which slow the waves - gives greater protection from flooding and erosion fairly cheap defences costs - starve beaches father down the coast of sand - makes them narrower narrower beaches don't protect the coast as well leading to greater erosion and floods

Question 52

Beach r - gives greater protection from flooding and erosion eplenishment

Answer 52

sand and shingle from lower parts of the beach or else where are added too the upper parts of the beaches benefits - creates wider beaches which slow the waves - gives greater protection from flooding and erosion costs - taking material from sea bed can kill organisms like sponges and corals very expensive defence and has to be repeated

Question 53

Slope stabilisation

Answer 53

slopes are reinforced by inserting concrete nails into the ground and covering the slope with metal netting benefits - prevents mass movement by increasing slopes strength costs - very expensive and sometimes difficult to install

Question 54

Strategic realignment

Answer 54

removing an existing defence and allowing the land behind it to flood benefits - overtime land will become marshland - creating new habitats flooding and erosion reduced behind the marshland costs - people may disagree over what land is allowed to flood for example - flooding farmland would affect farmers livelihoods

Question 55

What is Integrated Coastal Zone Management

Answer 55

an approach that aims to protect the coast while taking everyones interests into account