Coasts

Question 1

Define coast

Answer 1

Where the land meets the sea

Question 2

What type of environment is the coast and what does that mean

Answer 2

Dynamic meaning it’s constantly changing

Question 3

What is the coast shaped by

Answer 3

The dynamic environment of the sea
The earths natural processes including waves have resulted in the erosion growth and reshaping of the coast

Question 4

Why does the coastline change

Answer 4

Waves are the main force of coastal change

Question 5

What causes waves

Answer 5

Waves are caused by wind blowing over a stretch of open water called a fetch. The fetch is therefore the distance the wave travels

Question 6

What is a fetch

Answer 6

A stretch of open water

Question 7

What factors the waves size

Answer 7

The greater the fetch (distance travelled) the greater the wave
Yet wind speed can also greatly affect wave height, the stronger the wind the bigger the waves

Question 8

How do waves erode the coastline

Answer 8

They break on the shore releasing their energy
The larger the wave the more energy it releases and the more sediment it moves

Question 9

Explain the steps of a formation of a wave to its breaking

Answer 9

1. In open sea, the wind pulls on the surface of the water and causes it to rise
2. Inside the wave the water rotates and returns back to its starting point
3. As the wave approaches the beach/shallows it slows down. The lower section of the wave is slowed more than the upper section due to friction from the sea bed.
4. The wave will distort until the upper section forms a crest and topples over/breaks
5. At this point the energy of the wave will cause the water to move onwards either up a cliff face or surging up a beach (swash)
6. The water then retreats down the beach (backwash) or cliff face

Question 10

What did constructive waves do

Answer 10

Push material up the beach (deposition)

Question 11

What are the characteristics of constructive waves

Answer 11

Long in relation to their height
Gentle breaking at a rate of 6-9 waves per minute
Strong swash and weak backwash (allows them to bring more material up the beach than they bring back down)

Question 12

What do destructive waves do

Answer 12

Pull material out to sea (erode)

Question 13

What are the characteristics of destructive waves

Answer 13

They are high in relation to their length (scoop like a digger)
They form frequently breaking at a rate of around 15 per minute
They have a strong backwash in comparison to their swash (to allow them to drag more materiel away than they bring in)

Question 14

How is the seas force different to a river

Answer 14

The seas force is a much greater force and can move material around the world

Question 15

Corrosion/abrasion at the coast

Answer 15

Bits of rock and sand in waves grind down the cliff surfaces like sandpaper and may causes undercutting

Question 16

Attrition at the coast

Answer 16

Waves smash rocks and pebbles on the shore into each other reducing their size and making them more rounded

Question 17

Solution at the coast

Answer 17

Acids contained in sea water will dissolve rocks (such as chalk and limestone) from the seabed or cliffs

Question 18

Hydraulic action at the coast

Answer 18

The power of the sea (waves) can physically wash away soft rocks like boulder clay
When sea water breaks against a cliff air may become trapped widening cracks in the rock at the base of the cliff

Question 19

Traction at the sea

Answer 19

The rolling of large material along the sea floor by waves

Question 20

Saltation at the sea

Answer 20

The bouncing of slightly lighter material along the sea floor

Question 21

Suspension at sea

Answer 21

Small particles of material carried by the water

Question 22

Solution at sea

Answer 22

Material is dissolved and carried by the water

Question 23

What is called when material is moved in one direction more than the other by waves

Answer 23

Longshore drift

Question 24

How does longshore drift occur

Answer 24

Longshore drift occurs when waves hit a beach at an angle due to a prevailing wind direction
The swash moves up the beach at this angle but the backwash draws down straight
Over time the material is transported in the general direction of the wave along the coast

Question 25

How do coastlines grow

Answer 25

Waves contribute through deposition Material is added to the coastline by constructive waves to form beaches, spits and sand dunes

Question 26

When is deposition at the coast most common

Answer 26

Deposition occurs during periods of light winds and therefore the summer is the most common period for this process to occur in the UK

Question 27

Name coastal landforms that are created by the process of erosion

Answer 27

Headlands Cliffs Wave cut plat forms Caves Arches Stacks

Question 28

How is a headland formed

Answer 28

Stretches of coast do not erode evenly as sections of cliffs which are made of hard rock resist the hydraulic action and corrosive power of the sea compared to areas of soft rock. This means the soft rock will erode at a much faster rate than the hard rock eventually leading to the hard rocking sticking out. This is known as a headland

Question 29

What and why are found around headlands

Answer 29

Headlands face the full force of destructive waves and so are often the location of other erosion caused landforms like caves, arches and stacks

Question 30

What is a cliff

Answer 30

A cliff is a vertical rock face along the coast

Question 31

What is the shape of a cliff determined by

Answer 31

Geology: -soft rock eg.sand and clay erodes easily creating gently sloping cliffs -hard rock eg. chalk is more resistant and erodes slowly creating steep cliffs The way layers of rock are angled can also determine the shape of the cliff

Question 32

What is a wave cut platform

Answer 32

The narrow flat area seen at the base of a cliff produced by the retreat of the cliff as a result of erosional processes. It is only exposed at low tide

Question 33

How is a wave cut platform formed

Answer 33

1. A notch is formed in an area between high and low water marks due to corrosion (define) and hydraulic action (define). This area becomes a point of weakness. 2. The upper cliff face is then undercut and will eventually collapse 3. This happens over and over again until all the collapsed rock creates a wave cut platform at the base of the cliff 4. It is only exposed at full tide

Question 34

Give an example of a wave cut platform

Answer 34

Southern down South Wales

Question 35

Explain the formation of a cave, arch and stack

Answer 35

1.A wave cut notch (weak area produced by constant pounding of waves) can enlarging due to erosion and open up into a cave 2. Following further erosion the cave will become deeper and wider and erode through the headland by hydraulic action (define) and corrosion (define) to form a arch 3. The waves and weathering from the elements undermine the upper portion of the arch until it can’t hold its own weight up and collapses leaving a stack. 4. This collapses of the arch leads to the headland retreating. The stack will continue to be eroded by the sea forming a stump

Question 36

What is vital you mention when asked a question on formation of stacks

Answer 36

All landforms that come before it-notch,cave,arch Naming the erosional processes and DEFINE them

Question 37

Name landforms caused by coastal deposition

Answer 37

Beaches Spits

Question 38

Where and how are beaches formed

Answer 38

Beaches are formed in the intertidal area, which is the area that is exposed to air at low tide and underwater at high tide Here constructive waves push material like sand shingle and pebbles onto the coast Overtime this material can build up and be blown in shore by the wind to create a beach

Question 39

What is the cross section of a beach known as

Answer 39

Beach profile

Question 40

Why do beach profiles vary

Answer 40

Because of type of sediment and wave conditions

Question 41

Describe sandy beaches and give an example

Answer 41

On Sandy beaches the backwash of the waves continue to remove material (comb it back and smooth it) forming a gently sloping beach An example is Portstewart Strand

Question 42

Describe Shingle beaches and give an example

Answer 42

On shingle beaches the energy of a wave is reduced because the large particle (pebbles etc) size allows for percolation so the backwash is not very powerful and a steep beach is created An example is Ballygally Beach

Question 43

What are spits

Answer 43

Spits are depositional features made of sand that look like beaches A finger of sediment extends from the mainland out into the sea, often at a river mouth

Question 44

What conditions do you need for spits to form

Answer 44

4 conditions have to be met 1. Constant supply of sand or other material from erosion further up the coast. 2. Longshore drift operates most of the time 3. Coastline has a sudden change in direction to leave a sheltered Bay Area 4. The sea is quite shallow

Question 45

Why do spits occur

Answer 45

Due to Longshore drift When the material transported reaches a natural break in the coastline, the sand continues on and can build up breaking through the surface and forming a spit attached to the headland

Question 46

Give examples of a spit in UK

Answer 46

Spurn Head (Humber Estuary, UK)

Question 47

How can spits become hooked

Answer 47

Spits can be become established if they occur at an estuary as silt and mud from the river are deposited behind the spit making new land If the angle of the wave changes as the spit extends into the estuary the tip may turn to create a hooked spit 

Question 48

Explain the conditions and processes needed to form a spit (A S Z E N H C)

Answer 48

1. Waves approach the beach at an angle. 2. The swash carries material up the beach whilst the backwash comes straight down the beach. 3. The zigzag pattern means material is moved or transported along the coast in the process called longshore drift 4. as the coastline changes direction/shape the sand or shingle is deposited due to a lack of energy and accumulates. This area must be shallow. 5. This creates a narrow ridge. 6. this spit will grow over time as more material is deposited and if the waves changed direction or there is a river estuary the spit may curve to form a hooked spit 7. Spits require a constant supply of sand or they will be washed away

Question 49

Name coastal zones

Answer 49

Waters Shores Islands Salt marshes Beaches

Question 50

Why do we need coastal defence

Answer 50

1. People live near the coast. 2. Coastal areas are important economically. 3. Coastal areas are under threat due to rising sea levels (as a result of climate change).

Question 51

Why is coastal defence necessary for people who live near the coast

Answer 51

-In most continents around the world (except Africa) people are concentrated along the coastline -The coastline is the most populated zone on the planet; 3.2 billion people live within 200 km of the coastline -People like the view and as a result house prices along the coast are often very high. These expensive houses need protection.

Question 52

Why is coastal defence necessary economically

Answer 52

Many coastal areas rely on ports for effective transport links eg. railway lines Industry is also also often based in coastal areas In recent years, the tourism industry in Northern Ireland has grown. Hotels guest houses and caravan parks are found in coastal areas near key attractions such as the Titanic Quarter and the Giants Causeway.

Question 53

Why is coastal defence necessary for dealing with climate change

Answer 53

The greenhouse effect has caused global temperatures to rise Global warming over recent years is causing the global climate to change One direct effect is an increase in the rise of sea levels (due to melting ice caps) In the UK sea levels around the UK have risen by 10 cm If the sea levels continue to rise many low lying areas such as the Netherlands and Bangladesh are going to suffer severe consequences

Question 54

What do coastal areas need management for and what are the two types of methods?

Answer 54

Coastal areas need management to: -keep the sea out -retain cliffs and beaches The two main methods are hard engineering and soft engineering

Question 55

Hard engineering at the coast

Answer 55

Hard engineering involves building artificial structures along the coastline to reduce the erosion or manage deposition

Question 56

What are the 3 main types of hard engineering used on our coastlines

Answer 56

Seawalls Gabions Groynes

Question 57

What is a sea wall and what does it look like

Answer 57

Sea walls are the most common way to keep the sea bay They look like tall concrete walls built at the back of beaches They may have a curved shape which is designed to deflect their erosive energy of the wave and add extra protection against waves topping the wall

Question 58

What are the pros and cons of a sea wall

Answer 58

Pros: -They can be economically acceptable if they are needed to protect many people and properties -Prevent coastal flooding and some areas Cons: -they are expensive to build and the need for constant maintenance means costs continue -overtime the wall may be eroded

Question 59

What are Gabions and what do they look like

Answer 59

Gabions can be used successfully as short-term measures to stabilise cliff bases A Gabion is a metal cage measuring 1m by 1m that is built on site filled with local rocks and surrounded with six metal mesh sides

Question 60

What are the pros and cons of Gabions

Answer 60

Pros: -are relatively cheaper than other sea defences Cons: -As gabions rust and can be damaged during severe storms they do not provide a long-term solution to coastal management. They have an expected lifespan of 20-25 years.

Question 61

What are Groynes and what do they look like

Answer 61

Groynes are used when longshore drift is displacing sand from a beach Groynes are often made of hardwood and look like low fences stretching along a beach at intervals of about 50 m

Question 62

What are the pros and cons of Groynes

Answer 62

Pros: -they slow down longshore drift and promote deposition of sand building up beaches Cons: -The wood will eventually weather down (rot) and so Groynes have a lifespan of about 20 years -they can cause problems of public access along a beach -they can lead to extra erosion further down the coast as beach material cannot move naturally by longshore drift

Question 63

What does soft engineering involve at the coast

Answer 63

Soft engineering does not involve the large scale building required for hard engineering methods and often take advantage of natural processes to be effective. They have low cost economically and environmentally.

Question 64

What are the two main types of soft engineering used on our coastlines

Answer 64

Beach Nourishment or re nourishment Managed retreat

Question 65

What is beach nourishment

Answer 65

Each nourishment is sometimes called beach recharging Sand is dredged from the seabed and added to eroded beach or even brought in as lorry loads to add extra material along a stretch of coastline

Question 66

What are the pros and cons of beach nourishment

Answer 66

Pros: -can result increased tourism in the area -Beaches act as a natural sea defence for land behind Cons: -It is not a permanent fix -Nourished beaches erode faster than natural ones because the sand is not as tightly packed

Question 67

What is managed retreat

Answer 67

Due to environmental or economic costs the decision may be made to allow the sea to gradually flood land and erode cliffs Any people living near the coast may be compensated for lost land and demolished buildings

Question 68

What are the pros and cons of beach management

Answer 68

Pros: -natural processes are allowed to happen -Create sediment from erosion that will move and be deposited along the coastline forming a beach and thus protection -cheaper long-term than building and maintaining hard engineering strategies Cons: -compensation has to be paid -upsetting for landowners who lose land/buildings