Coasts Flashcards
1
Q
What is the littoral zone?
A
Wider coastal zone stretching into the sea and onto the shore. Dynamic interaction in the littoral zone leads to rapid change.
2
Q
What are the 5 parts of the literal zone, from land to sea?
A
Coast
Backshore
Foreshore
Nearshore
Offshore
3
Q
What is the foreshore?
A
Zone between high and low tide mark
4
Q
What are the 3 reasons as to why the littoral zone is a dynamic zone of rapid change?
A
- Marine + terrestrial processes operate + interact
- Extreme events
- Varying human development
5
Q
What is the difference between a primary and a secondary coastline?
A
Primary- formed via river deposition/volcanic lava
Secondary- formed via marine erosion/deposition
6
Q
What are the 3 short-term processes used to classify coasts?
A
River inputs (extent of deposition)
Waves (high/low energy)
Tides (high/low range)
7
Q
What are the 2 long-term criteria used to classify coasts?
A
Geology (hard/soft rock)
Sea level change
8
Q
In terms of the UK, where are rocky coastlines / coastal plains found?
A
Rocky- north-west UK
Plains- south & east of UK
9
Q
What are 5 features of a rocky coast?
A
- Erosion dominant but slow
- Erosional features
- Geology resistant to erosion
- High-energy environment
- High or low relief
10
Q
What are 4 features of a coastal plain?
A
- Depositional features
- Formed by coastal accretion
- Low-energy environment
- Low relief
11
Q
What are the 2 types of coastal plains?
A
Sandy (marine deposition)
Estuarine (river deposition)
12
Q
What is coastal accretion?
A
Continuous net deposition of sediment, leading to seaward growth, stabilised by vegetation
13
Q
How does the cliff face differ between rocky and plain cliff profiles?
A
Rocky- steep face
Plain- curved, lower angle face
14
Q
What is a concordant coastline, and give an example
A
Alternating layers of geology are parallel to the coast
Eg: south coast of Dorset
15
Q
What is a discordant coastline, and give an example
A
Alternating layers of geology are perpendicular to the coast
Eg: east coast of Dorset
16
Q
What are the 2 types of concordant coastlines?
A
Dalmation and Haff
17
Q
Where are Dalmatian and Haff coastlines found?
A
Dalmatian- Croatia
Haff- Baltic sea
18
Q
How are Dalmatian coasts formed in 3 steps?
A
- Folds are parallel to the coast (concordant)
- Tectonic folding caused ridges (anticlines) and valleys (synclines) parallel to the coast
- At the end of the glacial period, sea level rose leaving narrow islands
19
Q
How are Haff coasts formed in 2 steps?
A
- In glacial period, seawater level was lower and meltwater rivers deposited thick layers of sand + gravel to outwash plains
- In interglacial, sea level rise and constructive waves pushed the sand ridge to form a bar and traps river water (lagoon/Haff)
20
Q
How is the formation of headlands and bays an example of a negative feedback loop in 2 steps?
A
- Coastal retreat occurs due to alternating bands of hard/soft rock
- Headlands protrude and are more exposed to erosion, accentuated by wave orthogonals and wave refraction
21
Q
What is geological structure?
A
Layout of geology in coastal zone
22
Q
What are the 6 elements that geological structure consists of?
A
Strata
Bedding planes
Joint
Folds
Faults
Dips
23
Q
What are bedding planes?
A
Horizontal cracks, natural break in strata due to the gap in time between rock formation
24
Q
What are strata?
A
Layers of rock
25
What are joints?
Vertical cracks, fractures from contraction as sediment dries out, or tectonic uplift
26
How are folds created?
Pressure during tectonic activity makes rocks buckle and crumble
27
How are faults created?
Pressure on a rock exceeds its internal strength so fault slips along fault planes
28
What is a dip?
The angle at which rock strata lie
29
What are the 5 types of dips?
Horizontal strata
Gentle seaward dip
Steep seaward dip
Rocks dip inland
Rocks dip inland with joints
30
Describe horizontal strata and the risk of erosion with this dip
Steep cliffs
Fairly stable so low risk of erosion
31
Describe gentle seaward dip and the risk of erosion with this dip
Almost vertical joints opened by weathering + pressure release
Risk of erosion from gravity
32
Describe steep seaward dip and the risk of erosion with this dip
Rock slabs slide down cliff along bedding planes
Risk of erosion due to gravity
33
Describe rocks dip inland and the risk of erosion with this dip
Stable, steep cliff profile
Low risk as stable
34
Describe rocks dip inland with joints and the risk of erosion with this dip
Well-developed joints at a right angle to bedding plane
Fairly stable, but some risk as joints act as slide planes
35
What are the 3 steps as to how a wave-cut platform is formed?
1. At high tide, destructive waves hit the base of the cliff, and hydraulic action and abrasion form a wave-cut notch
2. The wave-cut notch undercuts cliff leaving destabilised overhang
3. The overhang collapses, and the cliff retreats leaving a wave-cut platform
36
What are the 4 steps as to how a cave/arch/stack/stump is formed?
1. Rocks have joints/faults (eg: limestone), hydraulic action and abrasion create cave
2. Two caves join or one erodes through creating an arch enlarged at the base
3. The top of the arch becomes unstable and collapses leaving a stack
4. The stack is vertically eroded to form a stump visible at low tide
37
What is an example of a WCP on the Jurassic Coast?
Kimmeridge bay
38
What is an example of folds on the Jurassic Coast?
Lulworth crumple
39
What is an example of an arch on the Jurassic Coast?
Durdle Door
40
What is an example of a concordant feature on the Jurassic Coast?
Lulworth Cove (chalk behind stops retreating, so expanding horizontally)
41
What is lithology?
The physical properties of a rock
42
What are the 3 types of bedrock lithology?
Igneous
Metamorphic
Sedimentary
43
How is igneous rock formed?
Cooling + solidifying of lava/magma either intrusive or extrusive
44
What are 3 examples of igneous rock?
Granite
Basalt
Pumice
45
What is the rate of erosion for igneous rock?
Very slow (less than 0.1cm/year)
46
Give 2 reasons why the rate of erosion for igneous rock is very slow
Composed of interlocking crystals making strong hard rock
Few joints/weaknesses that erosion would exploit
47
How is metamorphic rock formed?
Recrystallisation of igneous/sedimentary rock via heat and pressure, occurs deep at plate boundary
48
What are 3 examples of metamorphic rock?
Marble
Slate
Schist
49
What is the rate of erosion for metamorphic rock?
Slow (0.1-0.3 cm/year)
50
Give 3 reasons why the rate of erosion for metamorphic rock is slow
Crystalline so resistant
Foliation, crystals orientated in same direction, weaknesses
Heavily folded + fractured
51
How is sedimentary rock formed?
Compaction + solidification of deposited sediments
52
What are 4 examples of sedimentary rock?
Sandstone
Limestone
Chalk
Shale
53
What is the rate of erosion for sedimentary rock?
Moderate to fast (0.5-1 cm/year)
54
Give 3 reasons why the rate of erosion for sedimentary rock is moderate to fast
Most are clastic, broken pieces of old rock
Age, rock is younger so weaker
Many bedding planes and fractures
55
What is lithification?
When unconsolidated material is compacted + cemented to become consolidated sedimentary rock
56
What is unconsolidated material?
Younger, loose material that hasn't compacted so is vulnerable to erosion
57
What is pore water pressure, and how could this lead to potential erosion in a complex cliff profile?
Pressure water experiences due to the weight of the water above it
Can lead to a line of weaknesses
58
How can groundwater flow through rock layers weaken rock?
Removes cement that binds sediment together
Also creates high pore water pressure
59
What is permeable rock, and give 2 examples
Allows water to flow through
Eg: sandstone, limestone
Unconsolidated material is porus
60
What is impermeable rock, and give some examples
Doesn't allow groundwater flow
Eg: clays, mudstones, metamorphic + igneous
61
What are 3 ways in which vegetation can stabilise coastlines?
Plant roots can bind sediment together to reduce erosion
Leaves can slow wind speed at ground level, reducing erosion and increasing deposition
Plants die, adding humus (organic matter) to the soil
62
What are pioneer species?
First plants to colonise freshly deposited sediment
63
What is a climatic climax community?
Final community adjusted to climatic conditions of the area
64
What is the term for a sand dune succession?
Psammosere
65
What type of plants colonise sand dunes and why?
Xerophytic plants (dry tolerant)
66
Describe the sand dune succession
Embryo dunes → fore dunes → yellow dunes → grey dunes → dune slack → pine woodland
67
Why are there non-xerophytic plants towards the end of sand dune successions?
Improved nutrients (humus)
Above high tide, less saline
Improved water retention
68
How does soil pH change in dune successions as soil has more humus?
8.5 → 4.5
69
What are 3 examples of plants in a dune succession?
Marram grass
Gorse
Heather
70
What is the term for a salt marsh succession?
Halosere
71
What type of plants colonise muddy salt marshes and why?
Halophytic (salt tolerant)
72
Describe the salt marsh succession
Algal → pioneer → lower salt marsh/establishment → stablisation →higher salt marsh/climax
73
What may be found at the climax of a salt marsh succession?
Deciduous oak forest
74
What are 3 examples of plants in a salt marsh succession?
Eelgrass
Cord grass
Sea aster
75
How do waves form in 3 steps?
1. Wind creates frictional drag with the sea surface, which builds up
2. Shallow continental shelf creates friction with the sea bed, the circular orbit becomes increasingly elliptical
3. Wavelength shortens and the amplitude of the wave increases until the crest outruns the trough and breaks forward
76
What are the 4 factors affecting wave size?
1. Strength of wind
2. Duration of wind blowing
3. Water depth
4. Wave fetch (distance travelled)
77
What are 5 features of constructive waves?
1. Low-energy waves
2. Shallower + gently sloping nearshore
3. Long wavelength (up to 100m) but low frequency (6-8/min)
4. Low amplitude (<1m)
5. Swash > backwash as low angle of wave impact
78
As constructive waves cause beach gain, what feature is formed?
Berms
79
What are 5 features of destructive waves?
1. High-energy waves
2. Deeper + steeper nearshore so more circular orbit
3. Short wavelength (20m) but high frequency (13-15/min)
4. High amplitude (>1m)
5. Backwash > swash as it interrupts swash
80
As destructive waves cause beach loss, what feature is formed?
Offshore bars
81
What happens in summer to beach morphology?
Swash from constructive waves deposits larger material at the beach, creating a berm which weakens the backwash
82
What happens in winter to beach morphology?
Strong backwash transports and deposits sediment to form an offshore bar
83
How do beach sediment profiles vary?
Course + heavy sediment at the top of the beach (eg: gravel, shingle)
Finer sediment lower down the beach
84
What are tides?
The rise and fall of sea levels caused by gravitational pulling force exerted by the moon (and sun) and Earth's rotation
85
What is a tidal range?
Height difference between low and high tide
86
Why do tides occur?
Centrifugal forces and gravity in opposite directions results in a bulge of water around earth
87
Why do tides vary daily?
Earth's rotation means coastal locations past bulge 2x/day, so 2 high tides and 2 low tides
Earth and moon move slightly in their orbit, changing tide times slightly
88
Why do tides vary monthly?
Spring tide is highest high tide 2x/month, combined gravitational pull of sun and moon
Neap tide is lowest high tide 2x/month, solar tide not alined so decreased tidal range
89
How will beaches vary over longer periods?
Climate change, extreme weather means more winter profiles
Management interferes with sediment supply, decreasing beach size
90
How does hydraulic action work?
Air is trapped in cracks, compressed by waves which forces the crack open, it widens and this repeats
91
What is the influence of lithology on the impact of hydraulic action?
Heavily joined sedimentary vulnerable
Very hard igneous has cooling cracks, HA likely only process operating
92
How does abrasion (corrasion) work?
Sediment that waves pick up is thrown against the cliff
93
What is the influence of lithology on the impact of abrasion?
Softer sedimentary more vulnerable
Loose sediment must be available
Also, wave type + energy important
94
How does attrition work?
Eroded sediment is moved by waves, collisions chip rock to make smaller + rounded
95
What is the influence of lithology on the impact of attrition?
Softer rocks rapidly reduce in size, contribution to beach formation
96
How does corrosion (solution) work?
Alkaline rocks/binding cement is dissolved by sea + rain water
97
What is the influence of lithology on the impact of corrosion?
Mainly limestone as vulnerable to weak acids
98
What 2 things are erosion influenced by?
Waves
Lithology
99
What are the 4 transportation processes?
Traction
Saltation
Suspension
Solution
100
What are the factors that influence sediment transportation?
Angle of wave attack
Longshore drift
Tides
Currents
101
How can the angle of wave attack influence sediment transportation?
Determines the direction of sediment transportation
Swash aligned- wind directly on shore at 90° angle
Drift aligned- wind at an angle, leads to LSD, dynamic
102
What is longshore drift, and how can this process influence sediment transportation?
Net lateral transport of material when waves are at an angle
Swash transports material obliquely, with 30° the strongest move
Gravitational backwash moves sediment back down beach
103
How do tides influence sediment transportation?
Changes in sea level creates tidal currents
Transports sediment in the near/offshore
High tidal range = more powerful waves
104
What are currents and how do they influence sediment transportation?
Flow of water in a particular direction
Driven by winds, or temperature/density/salinity differences
Transports sediment in near/offshore
Can also be rip currents
105
When does deposition occur?
When waves no longer have sufficient energy for transportation
106
What are the 7 distinctive depositional coastal landforms?
Bayhead beaches
Recurved/double spit
Barrier beaches/bars
Barrier island
Offshore bars
Tombolo
Cuspate foreland
107
How are bayhead beaches formed, and give an example of one
Sediment accumulates at the back of a bay, by constructive waves, wave refraction disperses wave energy
Morfa Harlech, Wales
108
How are recurved spits formed, and give an example of one
Drift-aligned feature as coastline changes direction and sediment continues to deposit.
2 dominant wind directions lead to recurve, can also recurve via wave refraction depositing landwards
Hurst Castle spit
109
How are double spits formed, and give an example of one
2 spits from north/south ends of a bay
Poole Harbour
110
How are barrier beaches/bars formed, and give an example of one
Spit extends across a bay, or a ridge is driven back by constructive waves to form lagoon
Chesil Beach Dorset with Fleet lagoon
111
How are barrier islands formed, and give an example of one
Beach is separated from mainland, common in low tidal range with gently sloping offshore coastline
Large scale along Dutch coast
112
Where are offshore bars formed, and give an example of one
Where destructive waves break
Scroby Sands, Norfolk wind farm
113
How are tombolos formed, and give an example of one
Island causes wave refraction, so depositional
or
LSD builds spit across to island
Portland Bill to mainland Dorset
114
How are cuspate forelands formed, and give an example of one
Longshore drift from opposing directions
or
Converging of 2 spits- Dungeness Kent
115
What is the sediment cell concept?
Closed coastal subsystem of sediment sources, transfers and sinks along a coastline
116
How can you define a source in the sediment cell concept?
Releases more sediment than it absorbs
117
How can you define a transfer zone in the sediment cell concept?
Predominately sediment movement
118
How can you define a sink in the sediment cell concept?
Absorbs more sediment than it releases
119
What are 4 examples of sources?
Cliff erosion/sub-aeriel processes
River erosion
Aeolian sediment from land
Offshore bars
120
What are 3 examples of transfers?
Longshore drift
Currents + (rip)tides
Swash/backwash
121
What are 4 examples of sinks?
Backshore- sand dunes
Foreshore- beaches
Nearshore- bars
Offshore- barrier islands
122
Give a real-world example of the sediment cell concept
Flamborough head --> Holderness coast --> Spurn head
123
What is dynamic equilibrium in the sediment cell concept?
Inputs and outputs of sediment are equal so the size of landforms in the transfer zone remain the same
124
How do negative feedback loops rebalance systems in the sediment cell concept, using 2 examples?
Cliff collapses → eroded material protects coast from further erosion
Sand dune erosion → growth of offshore bar → barrier to destructive waves
125
How do positive feedback loops increase the original change in the sediment cell concept, using 2 examples?
Wind erosion removes stabilising vegetation → more erosion even in low velocity wind
Groynes trap sediment → terminal groyne syndrome → sediment starvation
126
What is the sediment budget?
Difference in the volume of sediment in a system and the sediment entering/leaving
Can be neutral/positive/negative
127
What is weathering?
The gradual breakdown of rock, in situ, creating sediment which the sea uses to erode the coast
128
What are the 3 types of mechanical weathering?
Freeze-thaw weathering
Salt crystallisation weathering
Wetting and drying
129
How does freeze-thaw weathering work in 3 steps? What are 2 conditions increasing the likelihood of this occurring?
1. Water enters a crack/joint
2. Water freezes and expands by approximately 10%, and this pressure results in cracks widening
3. This process repeats, and angular rock fragments collect at the bottom of the cliff as scree
Climate must have temperature that fluctuates both above and below 0°C
More likely in permeable/porous rock eg: chalk
130
How does salt crystallisation weathering work in 2 steps? What are 2 conditions increasing the likelihood of this occurring?
1. Saltwater penetrates cracks/pores at high tide
2. Evaporates at low tide, leaving salt crystals to grow and exert stresses in rock, breaking into angular fragments
Porous + fractured rocks eg: sandstone
131
How does wetting and drying work in 3 steps? Mention what type of rocks this occurs in
1. Rocks rich in clay (eg: shale) are soaked at high tide and expand
2. At low tide, the minerals dry and shrink
3. Repeated expansion and contraction cycles results in rock fragmenting and crumbling
132
What are the 3 types of chemical weathering?
Carbonation
Hydrolysis
Oxidation
133
How does carbonation work? What type of rock increases the likelihood of this occurring?
Weak acid rain mixes with calcium carbonate to form easily soluble calcium bicarbonate solution
Carbonate/sedimentary rocks eg: limestone
134
How does hydrolysis work? What type of rock increases the likelihood of this occurring?
H+ ions in water breaks down materials to form a clay and new solution
Igneous and metamorphic rocks containing feldspar
135
How does oxidation work in 2 steps? What type of rock increases the likelihood of this occurring?
1. Oxygen combines with iron-based minerals in rock
2. Iron oxide is created, increasing volume leading to rock breakdown
Rocks with iron compounds eg: sandstones, shales
136
What are the 2 types of biological weathering?
Plant root
Rock boring
137
How do plant roots lead to biological weathering in 3 steps? Where is this a key process?
1. Roots grow into cracks/fissures
2. Roots expand and thicken
3. The tensional force widens cliff and angular fragments break away
Important on vegetated cliff tops- can lead to rockfalls
138
How does rock boring lead to biological weathering? What type of rock is this likely to happen with? Where is this a key process?
Species (eg: molluscs) scrape at rocks with sharp shells, for food or home
Softer, sedimentary rock eg: shale
Foreshore as marine animals
139
What is mass movement?
Downslope movement of material when gravitational forces exceed resisting forces
140
What are the 4 factors that mass movement is influenced by?
1. Angle of slope/cliff
2. Rock type + structure
3. Vegetation cover
4. Wetness of ground
141
What are the 4 mass movement processes?
1. Blockfall/rockfall
2. Landslides
3. Rotational slumping
3. Flows
142
What is blockfall/rockfall, and why does it occur?
Small stones/larger rocks fall rapidly
Occurs when strong + jointed steep cliffs are exposed to mechanical/ freeze-thaw weathering
or
By marine erosion undercutting the cliff (wave-cut notch)
143
How do landslides work, and what can promote them?
Mechanical weathering/marine erosion undercutting alongside gravity works along a slip plane
Rain can lubricate slide plane and reduce resistance
Occurs on jointed rock with seaward dip
144
What is rotational sumping, on what rock type does it occur, and what is it facilitated by?
Single mass moves slowly on a curved rock plane
Occurs in weak rock, or with complex geology eg: permeable strata over impermeable beds
Facilitated by water (added weight and lubrication)
145
What are flows (mass movement) and how to they work? What can contribute to them?
Earthflows (more vigorous + larger sediment) /mudflows occur when fine/unconsolidated sediment mixes with water, so is saturated and flows downslope
Heavy rain + high tide contributes
146
What landforms are created by rotational slumping?
Rotational scars + terraces
147
What landform is created by rockfall?
Talus scree slopes, with large boulders at core and smaller material on top
148
What are the 2 types of longer-term sea level rise?
Eustatic
Isostatic
149
How can eustatic sea level rise occur?
At end of glacial period, land ice melts and returns to sea, lead to rise of approx 120m
Temperature increases, so thermal expansion occurs (heat results in the volume of ocean water increasing)
150
How can eustatic sea level fall occur?
During the glacial period, water evaporated and froze as land ice
151
How can isostatic sea level rise occur? (fall in local land level)
Subsidence- deposition or buildings leads to crustal sag
Post-glacial adjustment
152
How can isostatic sea level fall occur? (rise in local land level)
Accretion in sink regions builds up land
Post-glacial adjustment
153
In the glacial period, how was the UK adjusted?
The weight of the land ice in the NW depressed the crust
Forced solid lithosphere down, and as rigid, SE uplifted in the see-saw effect
The NW covered in ice up to Birmingjam
154
How has post-glacial adjustment occurred in the UK?
Melting of land ice, so NW crust is rebounding upwards by 1.5mm/year
UK is pivoting, south lowering by 1mm/year
155
How have tectonics caused eustatic sea level rise? Give an example
Rising magma at constructive margins/hotspots lifts crust, reducing global capacity of the ocean
0.1mm eustatic rise in the Indian Ocean
156
How have tectonics caused isostatic sea level change? Give an example
Folding of sedimentary rock -> anticlines and synclines -> fall + rise
Lava/ash produces fall eg: Hawaiian island chain
157
When do emergent coastlines appear?
When a fall in sea level exposes land previously covered by sea
158
What can be seen at emergent coastlines?
Raised beaches
Fossil cliffs
May see raised stacks/stumps
159
When do submergent coastlines appear?
When a rise in sea level floods the coast
160
What are the 3 types of submergent coastlines?
Ria
Fjord
Dalmation
161
What do rias look like? Where can one be found?
Steep-sided V-shaped valleys
Plan profile mirrors meander course with tributaries
South coast of Devon
162
How are rias formed?
Rivers erode the valley into frozen landscapes in a periglacial (cold) climate
Sea floods a river valley
163
What do fjords look like? Where can one be found?
Steep straight-sided U-shape valley with a shallow entrance
West coast of Norway, 205m long
164
How are fjords formed?
Glacial erosion cuts deep into landscape
Glaciers truncate spurs for a direct downslope route (straight sides)
Sea floods glacial valley
165
How are Dalmatian coasts formed (submergent coastline) in 2 ways?
Series of river valleys flooded that flow next to coast
or
Tectonic folding
166
What is the IPCC?
Intergovernmental panel on climate change
167
What are the IPCC's predictions for how global warming can contribute to eustatic sea level rise?
50% due to melting of land ice
40% due to thermal expansion
10% due to tectonic activity -> geothermal heat -> eustatic rise
168
By how many metres have sea levels risen since the last Glacial?
125m
169
What is the IPCC's new prediction for sea level rise? Why has this changed?
In 2013, between 28cm-98cm rise by 2100
Rate of sea level rise is increasing
170
Give 3 reasons as to why there is uncertainty in the IPCC's predictions for sea level rise?
Uncertain about relationship between GHGE increase and global warming
Uncertain about the rate of population growth + economic growth affecting GHGE
Uncertain about political commitment to reductions in GHGE
171
What places are most at risk from sea level rise?
Low-lying coastlines/islands
eg: Maldives
172
What are the 2 physical reasons for rapid coastal recession?
Geological
-lithology
-geological structure
Marine
-fetch
-strength of LSD
173
What are the 3 human actions causing rapid coastal recession? How do these actions cause the recession?
Dredging
Dams
Groynes
Interrupts sediment cell cycle, leading to sediment starvation
174
What is dredging and why is it done?
Sediment is scooped/sucked up for construction or boat navigation
175
What do dams do?
Store water and generate electricity, but traps river sediment
176
What do groynes do?
Wooden structure built to limit the movemnt of sediment
177
What happened to erosion rates in the Nile Delta? What is another factor that influences erosion rates?
Aswan High Dam constructed reducing sediment volume from 130 million tonnes/year to 15 million tonnes/year
Erosion rates from 25m/year to over 200m/year
But is on low lying land
178
Dredging in California has led to what % of the coastline facing critical erosion? What is an alternative explanation for this?
81%
Also 'el niño' storms and soft sandstone cliffs
179
What are 6 players that may alter natural systems?
Businesses
Residents
(Local) governments
Farmers
Mining industry
Environmentalists
180
What are 2 short-term factors that can affect the rate of erosion?
Tides
Weather systems/storms
181
How can tides affect the rate of recession short-term?
Daily high tide x2 increases cliff erosion
Monthly spring tide x2 increases recession
182
How can storms affect the rate of recession short-term and medium-term?
During + after events larger waves attack + soak cliff
More storms in winter
183
What are 2 long-term factors that can affect the rate of erosion?
Wind direction + fetch
Sea-level rise
184
How can wind direction + fetch affect the rate of recession long-term?
A dominant prevailing wind direction with a larger fetch leads to more coastal recession
185
Why is the Holderness coast the fastest retreating coastline in Europe?
Low-pressure weather system- more storms, even more in Winter
Swell/current circle the UK and adds energy to the waves
In an enclosed sea with nowhere to dissipate energy
186
What are 3 local factors that increase flood risk on some low-lying and estuarine coasts?
Height
Degree of subsidence
Vegetation removal
187
How can height (of land) increase flood risk?
Low-lying coastlines are at temporary risk from storm surges, but also permanent risk from global sea level rise
188
How does height in the Maldilves affect flood risk? What have they done to combat this?
Highest point is only 2.3m above sea level
The capital Male is protected by a 3m high sea wall
189
In Bangladesh, how can height affect flood risk?
60% is less than 3m above sea level
190
What is subsidence?
The settling and compaction of sediment
191
How can subsidence increase flood risk?
Deltas experience isostatic subsidence, and the crust depresses
or
Groundwater abstraction reduces sediment volume
192
How has subsidence affected Bangladesh?
50 large islands in the delta have subsided 1.5m since 1960
193
How does vegetation removal increase flood risk?
Salt marshes + mangrove forests no longer trap sediment + stabilise existing sediment, also won't absorb wave energy
194
How are mangrove forests being removed in Bangladesh?
71% retreating by 200m/year
195
What is a storm surge?
Temporary rise in sea level caused by storms
196
What are 5 dramatic short-term impacts from the UK/Netherlands 2013 storm surge?
1000 homes flooded
2 died
All rail services cancelled in Scotland
Thames Barrier + Eastern Scheldt storm surge barrier closed
£100mil in UK damage
197
What are 5 dramatic short-term impacts from the Bangladesh 2007 cyclone Sidr?
Infrastructure + electricity damaged
Up to 10,000 died
Coastal and river embankments breached --> flooding + drinking water polluted
Sanitation infrastructure destroyed, risk disease
Almost US$30 mil damage
198
What are the 2 types of storms?
Tropical cyclones 8°-20º N/S of equator by the evaporation of warm sea water
Mid-latitude depressions by the meeting of hot and cold air
199
Is the data between climate change and tropical storm frequency clear?
No
Atlantic storms have a slight positive correlation, but no clear trends in other areas
200
Why is it hard to predict how climate change may affect the pace and magnitude of coastal flood risk?
Low evidence for the predicted increase in storms (although high evidence for the predicted increase in sea level)
furthermore...
-complex physical systems
-thermal expansion poorly understood
-will people and governments change?
201
How may human geography worsen storms?
Population growth
Development
Land use (deforestation)
Coastal management
202
Via mitigation, how can the effects of climate change be reduced?
Decarbonising
-reduce fossil fuel use
-increase use of renewable energy
203
Via adaptation, how can the effects of climate change be modified?
Large sea walls
Reafforestation
204
Why are geographers pro-mitigation with some adaptation?
Although expensive, mitigation is an investment and is also becoming cheaper
205
What are 4 economic losses from coastal recession?
Housing
Businesses
Agricultural land
Infrastructure
206
What are 3 social losses from coastal recession?
Relocation
Loss of livelihood
Amenity value
207
What is the economic loss of the lifeboat centre (infrastructure) under threat at the Holderness? What is the social loss of this (livelihood)?
Can't guide ships with goods to Humber Estuary
Safety jeopardised
208
Why is the tourism industry (business) disrupted in the Holderness?
Erosion of beach dangers Tunstall caravan site
209
Which road (infrastructure) of economic importance is under threat from recession in the Holderness?
Main road by Hornsea and Withernsea
210
How much agricultural land is lost to coastal recession /year in the UK? What is the knock-on effect of this?
80,000m²
Farmers give up some of the best land to diversify
211
What is the economic loss regarding houses in an area of coastal recession?
Hard to get mortgages on properties, especially with no hard engineering- people trapped
212
What is the economic cost that Easington Gas Terminal is under threat (infra/business)?
Supplies 25% of GB's gas
213
Why do people relocate (social loss) due to coastal recession?
Houses falling into sea
214
How many villages have been lost in the Holderness from coastal recession (social loss)?
32 since Roman time, 3 under threat
215
What is amenity value? How can coastal recession impact this?
Place has worth as generates pleasant feelings
Loss of homes + community = loss of amenity value
216
How have farms been impacted in the Holderness from coastal recession?
Ringborough farm loses 1-2m/y, diversified to gas
Loss of livelihood for small farms
217
Which part of the Holderness coast hasn't had major economic/social losses due to hard engineering protection?
Mappleton
Improved local community
Businesses had confidence to invest- local economy grew
218
What are environmental refugees?
People forced to leave home due to sudden/LT changes in their local environment, compromising well-being/secure livelihood
219
How many environmental refugees does IPCC predict to have by 2050- why?
200 million
Climate change is increasing sea level rise leading to:
- Flooding
- Saltwater encroachment
- Coral Bleaching (a sea defence)
220
What are the 2 case studies for environmental refugees?
Pacific SIDS- Tuvalu
Fairbourne, Wales
221
Give background for Tuvalu, where there are environmental refugees
Population 11,000
Mostly 1-2m above sea level
Very remote for tourism, ignored
May be inhabitable in 50-100 years
222
What are 4 reasons why there are environmental refugees in Tuvalu?
Weather becoming less predictable
Fish poisoned from algae from bleached coral, can poison humans
High population density- no space for relocation
Lacks funds for coastal defenses
223
Give background for Fairbourne, Wales, where there are environmental refugees
Population 1000
UK's very first environmental refugees
224
What are 2 reasons why there are environmental refugees in Fairbourne?
Increasingly regular flooding, ferocious storms
Sea wall may be swept away
225
Why is it hard for people to become an environmental refugee from Fairborune?
Hard to sell homes (or get mortgage!)
Hard to relocate in Wales as English speaking
226
What is hard engineering?
Traditional management for recession/flooding by directly altering or stopping physical processes
227
What are 5 hard engineering strategies for coasts?
Groynes
Sea walls
Rip rap
Revetments
Offshore breakwaters
228
How do groynes work?
Traps sediment moved by LSD, creating a beach where waves crash- not at cliff
229
What are 3 advantages of groynes?
Beach build up has tourism potential
Works with natural processes to build beach
Cheaper than sea wall (£2500-5000/m)
230
What are 3 disadvantages of groynes?
TGS starves beaches downdrift as interrupts LSD
Unattractive + unnatural
231
How do sea walls work?
Physical barrier that reflects/dissipates waves
232
What are 3 advantages of sea walls?
Very effective
Long-lasting
Promenade to walk on good for beach access
233
What are 3 disadvantages of sea walls?
Expensive to build + maintain
Intrusive + unnatural
Can reduce sediment supply as reflects, doesn't deposit
234
What is rip rap and how does it work?
Large igneous/metamorphic rock in front of cliff, acts as a permeable barrier to break up + dissipate waves
235
What are 2 advantages of rip rap?
Relatively cheap to construct + maintain
Used for fishing/tourism
236
What are 2 disadvantages of rip rap?
Rocks don't fit in with local geology
Dangerous for people clambering
237
What are revetments and how do they work?
Sloping concrete/wood at cliff/beach to break up + absorb wave energy
238
What are 2 advantages of revetments?
Relatively cheap
Can be used to protect sand dunes/mud banks too
239
What are 2 disadvantages of revetments?
High maintenance, especially wood
Intrusive + unnatural
240
What are offshore breakwaters?
Partly submerged igneous/metamorphic rock barrier to break up/absorb waves before they reach the coast
241
What are 2 advantages of offshore breakwaters?
Improves safety for tourism/sports
Effective permeable barrier
242
What are 3 disadvantages of offshore breakwaters?
Usually unappealing, especially at low tide
Can be bad for navigation
Interferes with sediment transport
243
What is the 1949 coastal protection act?
Local authorities decide which areas to protect- in Holderness this is mainly 3 main population centres
244
How have Hornsea and Withernsea (2/3 main population centre) been protected?
Sea walls
Groyne field
Rip rap
245
How and why has Mappleton been protected?
Singlar rock groyne
Rip rap
Due to main road with regional importance
246
How has Easington gas terminal been protected?
Sea walls
Groynes
Rip rap
247
What place is affected by groyne management in the Holderness coast?
Humber Estuary- drains 1/7th of rivers in England
Sediment maintains the spit, but if this erodes from TGS, sea erosion occurs up River Humber
248
Why is there flooding threat in Bangladesh?
Soft geology
Storm surges
Mangrove destruction
249
What is the effectiveness of embankments controlling flooding in Bangladesh?
Raised mound to control flooding
BUT water is funnelled/constricted, so height/speed of water increases --> in overspill/floods
250
What is the effectiveness of poulders controlling flooding in Bangladesh?
Land enclosed by embankments for farming- have 139
BUT no natural nourishment from deposition, so lnd dries out + sinks (subsidence)
--> Bangladesh further threatened by rising sea level
251
What is soft engineering?
Attempts to work with natural processes to reduce coastal recession + flood threat
252
What are 3 soft engineering strategies for coasts?
Beach nourishment
Cliff regrading and drainage
Dune stabilisation
253
What is beach nourishment?
Artificially replenishing sediment on the beach to make it higher + wider
254
What are 3 advantages of beach nourishment?
Relatively cheap + easy to maintain
Looks natural, blends with existing beach
Bigger beach increases tourism potential
255
What are 2 disadvantages of beach nourishment?
Needs constant maintenance due to erosion + LSD
Sediment dredged offshore must be sustainable
256
What is cliff regrading?
Reduces the angle of the cliff to stabilise it
257
What is an advantage and disadvantage of cliff regrading?
Works on clay/loose rock where other methods don't
Actualy causes cliff to retreat
258
What is cliff drainage?
Removes water to prevent landslides/slumping by reducing pore water pressure
259
What is an advantage and disadvantage of cliff drainage?
Cost effective
Can dry out and collapse (rockfall)
260
What is dune stabilisation?
Marram grass stabilises when planted, then fenced to keep people away
261
What are 3 advantages of dune stabilisation?
Maintains natural coastal environment
Important wildlife habitats
Relatively cheap + sustainable
262
What are 2 disadvantages of dune stabilisation?
Time-consuming
Negative response from being kept off certain areas
263
How has soft engineering been done at Kilnsea, Holderness?
Natural floodbanks- affordable and local run as only 90 people
Sandy Beaches Caravan Park Rollback scheme- given land choice as lost to sea, 5 new spaces for every 4 lost as 50 already lost
264
How has soft engineering been done at Humber Estuary, Holderness?
Managaed realignment
Naturally, spit wants to move
Moveable road, although will probably go
265
What is coastal squeeze, that happened at Abbots Hall Farm?
Hard engineering preventing landward movement, so coastal margin is squeezed
Loss/deterioration of rare + valuable natural habitats eg: short-eared owl
266
Why was managed realignment chosen for Abbots Hall farm?
Existing flood defences on strain from rising sea levels, expensive
Natural gradient opens area for inter-tidal flood zone for habitat regeneration
Funding available eg: Essex Wildlife Trust
267
What are 3 benefits of the natural + sustainable MR at Abbots Hall farm?
Saltmarsh + mudflat + grass habitat
Decreased coastal squeeze
Internationally important to demonstrate managed realignement
268
How have stakeholders been considered in the management of Abbots Hall farm?
Fisherman downstream worried about sediment supply from HE
Erosion concerns
Locals engaged in decision making eg: open day
269
What are 3 methods of sustainable management of the Maldives?
Artificial island construction
Male 3m sea wall
Education on mangroves as a defence --> afforestation of mangroves
270
How does the global environment facility support economic growth in the Maldives?
Promotes organic farming as an alternative to overfishing via grants
271
What is the integrated coastal zone management (ICZM)?
Process bringing together all involved in development, management, and use of coast
Promotes sustainable socio-economic activity to reduce conflict, and protect the environment
272
Why has there been a historical change in the way coastlines are managed?
Rise of higher value seaside towns for tourism
Rio Earth Summit 1992 promoted sustainability
273
How are coastlines managed holistically?
Across political boundaries
Understanding change in one cell can impact elsewhere in cell
Planned LT
Works with natural processes, not against
Considers livelihood, local economy and biodiversity
274
What are the 4 decisions in the Shoreline Management Policy (SMP)?
Hold the line
Advance the line
Strategic realignment
No active intervention
275
What are 4 factors considered when making a complex judgement for the SMP?
Political/economic/social reasons
Engineering feasibility
Environmental sensitivity
Land value/use
276
How is the value of agricultural land decided to make a complex judgement over an SMP?
Graded for condition
277
What does environmental sensitivity include when making a complex judgement over an SMP?
Protecting historic sites
Protecting sites of specific scientific interest (SSSI)
Heritage coasts eg: Spurn Head
278
What are some management strategies not suitable for (in terms of engineering feasibility)?
Mobile depositional features eg: spit
279
What is a cost-benefit analysis?
Socio-economic + environmental advantages and problems of coastal defences are listed to help managers make final decisions on type of coastal defences implemented
280
What is an example of a cost-benefit analysis in Happisburgh?
Protection = farmland saved with value almost £1 million
Erosion = grade 1 listed St Mary's church lost
281
What is the Environmental Impact Assessment?
Identifies short + long term impacts of building coastal defenses or changing policy
eg: sediment flow, pollution, water quality
282
What is the SMP along the Holderness?
Mostly NAI as doesn't cost, but some economic losses (eg: building/land)
HTL at Bridlington, Hornsea, Withernsea as highly populated, Mappleton due to A-road, Easington Gas. Here benefit of protection > cost to build
SR at Spurn point allowed to evolve with minimal cost, also SSSI
283
What is the ICZM along the Odisha coastline, India?
Mangrove replanting
Hard engineering to control coastal erosion
Ecotourism
Cyclone shelters
284
Why is the ICZM needed in Odisha, India?
Large mangrove forest, rich in mineral deposits, fishing industry
Under stress from:
- rapid industrialisation
- tourism
- mining
- erosion
- cyclones
- rising sea levels
285
What is the management in Happisburgh?
Some groynes in the 50s
CBA led to NAI in immediate future, MR in medium-long term
Pathfinder Scheme to trial new ways of management eg: clifftop enhancement, caravan site removal
286
Why is there conflict + sense of injustice over the management and policy decisions in Happisburgh?
Local residents offered compensation, but lose communities + homes
Property value decreasing (negative equity)
Pathfinder scheme can attract local businesses, thus tourism, but farmland lost for this
287
Who is a winner for the management/policy decision in Happisburgh?
Local council saves money, less spent on hard engineering
288
Where is conflict over management/policy decisions avoided?
Abbotts Hall as all stakeholders considered
289
Why is shipbreaking a suitable job in Chittagong, Bangladesh?
Large tidal range, so ships stuck on mudflats
Available cheap labour
290
What is the conflict in management in Chittagong?
Hard engineering, or soft to prioritise environment
291
Why is there conflict in Chittagong?
Gov/shipyard owners (as v suitable) VS environmentalists/human rights activists (health issues, environmental issues eg: toxins, pollution)
Shipyard owners (money) VS fishermen (pollution = fish mortality, but fisherman lack formal job title for compensation)
Internal conflict without workers: should they risk fatalities?
292
What are 2 sustainable solutions for management in Chittagong?
Afforestation + mangrove plantations for ecosystem
Water ponds for animal drinking water
