Coasts

Question 1

Define ‘Littoral Zone’

Answer 1

Wider coastal zone - includes coastal land and shallow parts of sea

Question 2

What are the five sections of the Littoral Zone?

Answer 2

Coast > Backshore > Foreshore > Nearshore > Offshore

Question 3

Differentiate between Emergent and Submergent coasts

Answer 3

Emergent - Coasts rising relative to sea level

Submergent - Sea level is higher than coast, flooding occurring

Question 4

Define low energy and high energy coasts

Answer 4

Low energy - Sheltered, limited wave fetch, low wind speeds mean smaller waves
High energy - Exposed, high winds, longer fetch, bigger waves

Question 5

Differentiate between Discordant and Concordant Coastlines

Answer 5

Discordant - Differing rock types, running at a 90 degree angle to the coast, create uneven coastline, less resistant rock eroded to form bays, more resistant rock remains as headlands
Concordant - Different rock strata run parallel to the coast, vary in terms of resistance

Question 6

What is a cliff profile and what 2 things influence it most?

Answer 6

Cliff Profile - Height & angle of a cliff face, plus other features, e.g. wave cut notches
Influenced by resistance to erosion of its rock type(s) and the dip (angle) of the rock in relation to the coastline

Question 7

Describe 3 different kind of dips, and their effect on the cliff profile

Answer 7

Horizontal Dip - Vertical profile, notches reflect less resistant strata
Seaward dip high angle - Sloping towards sea, one rock layer facing the sea, vulnerable to rock slides down the slope
Seaward dip low angle - Profile may exceed 90 degrees, areas of overhanging rock, very vulnerable to rock falls

Question 8

What is the other major factor that affects cliff profiles?

Answer 8

Permeability of the rock strata - More permeable rock means groundwater infiltration, creating weaknesses

Question 9

What are the three rock types that influence coastal recession?

Answer 9

1) Igneous - Very slow erosion rate, crystalline rock, limited weaknesses that erosion can exploit
2) Metamorphic - Slow erosion rate, also crystalline however often folded and heavily fractured, forming weaknesses
3) Sedimentary - Moderate/Fast rate, geologically young rocks (weaker)

Question 10

How can permeability of rock strata affect erosion rates?

Answer 10

If the rock is permeable groundwater can weaken it by removing binding cement. Can also create pore water pressure (internal) within the cliff, affects stability

Question 11

How does coastal vegetation protect against recession?

Answer 11

Roots bind sediment particles together, makes them harder to erode
Submerged plants form a protective layer, ensure sediment is not directly exposed to water/erosion

Question 12

Define ‘Plant Succession’

Answer 12

The changing structure of a plant community over time, as

areas of bare sediment are colonised

Question 13

What are the factors affecting wave size?

Answer 13

Strength of the wind
Water Depth
Wave fetch (the distance waves have to grow in size)

Question 14

Differentiate between Constructive and Destructive waves

Answer 14

Constructive - Strong swash (flow of water up beach), sediment pushed up the beach
Destructive - Strong Backwash (water draining down the beach into the sea), sediment eroded & deposited offshore

Question 15

Why do wave types frequently vary?

Answer 15

Storms bring destructive waves, subside over the day and become constructive
Seasonal changes - Summer (constructive) vs Destructive (destructive)
Changes to climate - e.g. global warming bringing more storm seasons

Question 16

What are the four main processes that cause erosion?

Answer 16

Hydraulic Action - Waves compress air trapped within rocks, internal pressure forces cracks open, dislodges rocks from the cliff face
Abrasion - Sediment picked up by waves, thrown against cliff face, chiselling away at the surface
Attrition - Sediment slowly chipped away at/ made smaller over time, as it is transported around
Corrosion - Carbonate (limestone) rocks are vulnerable to solution by rainwater, seawater etc.

Question 17

Name four erosional coastal landforms

Answer 17

Cave, Arch, Stack, Stump

Question 18

How does a wave cut notch affect recession rates?

Answer 18

As notch becomes deeper, overhanging rock becomes unstable, leads to rock falls. Repetition of this process causes cliffs to recede inland

Question 19

What is longshore Drift, and what is it a key source for?

Answer 19

Longshore Drift - The net transportation of sediment along a beach, as a result of swash and backwash
Key source of a sediment for depositional landforms

Question 20

What are some of the way sediment is deposited?

Answer 20

‘Gravity Settling’ - Energy of transporting water becomes too low to move sediment, bigger sediment deposited first, followed by smaller sediment
‘Flocculation’ - Small sediment particles in water, e.g. clay, clump together & become big enough to sink

Question 21

Give 3 examples of Depositional Landforms

Answer 21

Spit - Sand extending beyond a turn of coastline, longshore drift spreads out & loses energy, leading to deposition
Bay-head Beach - Waves break at the shoreline, move sediment to a bay, where a beach forms
Tombolo - Sand/Shingle bar linking coastline to an offshore island

Question 22

Define the Subaerial processes of Weathering and Mass Movement

Answer 22

Weathering - The breakdown of rocks by chemical, mechanical or biological agents
Mass movement - Refers to the downslope movement of rock and soil

Question 23

Differentiate between mechanical, chemical and biological weathering

Answer 23

Mechanical - Breaks down rocks with physical force, no chemical change
Chemical - involves a chemical reaction & the generation of a new chemical compounds
Biological - Often speeds up mechanical/chemical weathering through action of plants etc.

Question 24

Give one example of Mechanical, Chemical and Biological weathering, respectively

Answer 24

Mechanical - Freeze Thaw, water expands as it freezes forcing existing cracks/fissures open, loosens rocks
Chemical - Carbonation, Slow dissolution of limestone due to rainfall
Biological - Plant roots, tree/plant roots grow in cracks/fissures, force rocks apart

Question 25

Give 3 examples of Mass Movement

Answer 25

Fall - Rockfalls, rapid form of mass movement, blocks of rock dislodged by weathering, notches etc. Topple - Where rock strata have a steep seaward dip (lean towards sea), undercutting quickly leads to instability & blocks of rock toppling Rotational Slide - Masses of material slowly rotate downslope, could take days or years

Question 26

Define Eustatic and Isostatic

Answer 26

Eustatic - Rise or fall in Sea level | Isostatic - Rise or fall in land level

Question 27

What is dredging and how does it effect coastal recession?

Answer 27

Process of removing sediment from sea/river bed, for use in construction Increases erosion along a coastline

Question 28

Why are low-lying coastal areas so densely populated?

Answer 28

Popular with tourists | Coastal plains are especially fertile, ideal for farming

Question 29

What is the most common cause of coastal flooding?

Answer 29

Storm surges - Localised short-term rise in sea level caused by air pressure change

Question 30

Give an example of a Concordant coastline and a Discordant coastline, respectively

Answer 30

Concordant - Lulworth Cove, South Coast (large bay has formed there) Discordant - Swanage Bay, South Coast

Question 31

Give an example of an High Energy and a Low energy coast, respectively

Answer 31

High Energy - Atlantic coastlines e.g. Norway Scotland | Low Energy - Mediterranean coasts

Question 32

Name two countries at risk from coastal flooding, and why they are at risk

Answer 32

Maldives - Average land level of 1.5m, lowest in the world, extremely susceptible to sea level rise (capital city surrounded by 3m high wall) Bangladesh - Especially vulnerable to tropical cyclone storm surges, Low-lying country, 1-3m above sea level, intense rainfall from cyclones increases flooding, deforestation has diminished interception

Question 33

What are the economic, social and environmental costs of storm surges?

Answer 33

Economic - Loss of property/businesses, loss of farmland Social - Loss of homes, deaths, people have to move away from their areas Environmental - Loss of habitat

Question 34

Give two examples of places that have experienced negative economic impacts as a result of storm surges?

Answer 34

``` UK, 2013-4 - Damage of around £1 billion over the course of the winter storms Hurricane Sandy (USA) - $70 billion in damage, 350,000 homes destroyed/damaged ```

Question 35

What are the four approaches to coastal management?

Answer 35

Hold the line- Creation or maintenance of sea defences along a coastline Managed retreat - Management and monitoring of the coast to allow coastal processes to take over gradually Advance the line - Building of new defences on the coastline, Land reclamation Do nothing - No active intervention

Question 36

Give examples of hard and soft engineering

Answer 36

Hard - Sea Wall, Groynes, Rip Rap | Soft - Beach nourishment, cliff regrading

Question 37

What are the benefits of each coastal management technique?

Answer 37

Sea Wall - Long lasting, give local people sense of security Groynes - Maintains size of the beach, less expensive than sea walls Rip Rap - Long lasting, flexible in use, can be placed on the backshore Beach nourishment - Aesthenically pleasing, supports tourism Cliff regrading - Creates natural looking slope, brings certainty to locals

Question 38

What are the disadvantages of each coastal management technique?

Answer 38

Sea Wall - Expensive (around £5000 per metre), not aesthetically pleasing Groynes - Also expensive £1000 per metre), can leave other parts of coast with less sediment Rip Rap - May look unsightly Beach Nourishment - Do not last long in winter conditions, have to replaced repeatedly Cliff regrading - Some land/property will be lost

Question 39

What is the ICZM?

Answer 39

Integrated Coastal Zone Management

Question 40

What are the 3 key characteristics of an ICZM?

Answer 40

1) Entire coastal zone is managed (includes all ecosystems, resources and human activity) 2) Recognises importance of coast to people's livelihoods, many people live and work on the coast 3) Recognises management of coast must be sustainable

Question 41

What 3 things does a Cost Benefit Analysis take into account?

Answer 41

Cost of erosion, benefits of protection, costs of sea defences

Question 42

Give an example of a place where 'Do nothing' has been implemented

Answer 42

Happisburgh: To protect land would impact on the wider coastal management plan. Would also cause greater erosion further down the coast.