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Physical Geography - Concepts > Coasts > Flashcards

Coasts Flashcards

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1
Q

Define ‘Littoral Zone’

A

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

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2
Q

What are the five sections of the Littoral Zone?

A

Coast > Backshore > Foreshore > Nearshore > Offshore

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3
Q

Differentiate between Emergent and Submergent coasts

A

Emergent - Coasts rising relative to sea level

Submergent - Sea level is higher than coast, flooding occurring

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4
Q

Define low energy and high energy coasts

A

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

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5
Q

Differentiate between Discordant and Concordant Coastlines

A

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

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6
Q

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

A

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

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7
Q

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

A

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

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8
Q

What is the other major factor that affects cliff profiles?

A

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

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9
Q

What are the three rock types that influence coastal recession?

A

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)

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10
Q

How can permeability of rock strata affect erosion rates?

A

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

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11
Q

How does coastal vegetation protect against recession?

A

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

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12
Q

Define ‘Plant Succession’

A

The changing structure of a plant community over time, as

areas of bare sediment are colonised

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13
Q

What are the factors affecting wave size?

A

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

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14
Q

Differentiate between Constructive and Destructive waves

A

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

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15
Q

Why do wave types frequently vary?

A

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

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16
Q

What are the four main processes that cause erosion?

A

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.

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17
Q

Name four erosional coastal landforms

A

Cave, Arch, Stack, Stump

18
Q

How does a wave cut notch affect recession rates?

A

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

19
Q

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

A

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

20
Q

What are some of the way sediment is deposited?

A

‘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

21
Q

Give 3 examples of Depositional Landforms

A

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

22
Q

Define the Subaerial processes of Weathering and Mass Movement

A

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

23
Q

Differentiate between mechanical, chemical and biological weathering

A

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.

24
Q

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

A

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

25
Q

Give 3 examples of Mass Movement

A

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

26
Q

Define Eustatic and Isostatic

A

Eustatic - Rise or fall in Sea level

Isostatic - Rise or fall in land level

27
Q

What is dredging and how does it effect coastal recession?

A

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

28
Q

Why are low-lying coastal areas so densely populated?

A

Popular with tourists

Coastal plains are especially fertile, ideal for farming

29
Q

What is the most common cause of coastal flooding?

A

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

30
Q

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

A

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

31
Q

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

A

High Energy - Atlantic coastlines e.g. Norway Scotland

Low Energy - Mediterranean coasts

32
Q

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

A

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

33
Q

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

A

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

34
Q

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

A 
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
35
Q

What are the four approaches to coastal management?

A

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

36
Q

Give examples of hard and soft engineering

A

Hard - Sea Wall, Groynes, Rip Rap

Soft - Beach nourishment, cliff regrading

37
Q

What are the benefits of each coastal management technique?

A

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

38
Q

What are the disadvantages of each coastal management technique?

A

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

39
Q

What is the ICZM?

A

Integrated Coastal Zone Management

40
Q

What are the 3 key characteristics of an ICZM?

A

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

41
Q

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

A

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

42
Q

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

A

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

Physical Geography - Concepts (3 decks)

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