1
Q
Input definition
A
Material or energy moving into the system from the outside
2
Q
Examples of input
A
-precipitation
-wind
3
Q
Output definition
A
Material or energy moving from the system to the outside
4
Q
Examples of ouput
A
-ocean currents
-rip tides
-evaporation
5
Q
Energy definition
A
Power or driving force
6
Q
Examples of energy
A
-energy associated with water
-the effects of gravity of cliffs
-moving air
7
Q
Stores / components definition
A
The individual elements or parts of a system
8
Q
Examples of stores
A
-beach
-sand dunes
-nearshore sediment
9
Q
Flows / transfers definition
A
The links or relationships between components
10
Q
Examples of flows / transfers
A
-wind blown sand
-mass movement processes
-longshore drift
11
Q
Positive feedback definition
A
Where a transfer leads to increase or growth
12
Q
Example of positive feedback
A
-coastal management in one area leads to an increase erosion further along the coast
13
Q
Negative feedback definition
A
Where a flow / transfer leads to decrease or decline
14
Q
Example of negative feedback
A
-when the rate of weathering and mass movement exceeds the rate of cliff erosion a scree slope is formed = protecting the base of the cliff from erosion
15
Q
Dynamic equilibrium definition
A
State of balance within a constantly changing system
16
Q
Example of dynamic equilibrium
A
-constructive waves build up a beach, making it steeper = encourages the formation of destructive waves that plunge -> redistributing sediment = encourages constructive waves
17
Q
How is the coast an open system
A
It has inputs that originate from outside the system and outputs to other natural systems
18
Q
What links does the coastal system have to other systems
A
Links with the atmosphere, tectonics, ecosystems and oceanic systems by flows and energy and transfer of material
19
Q
Sediment cell definition
A
A small stretch of coastline and nearshore area where sediment movement is largely self contained
20
Q
What is the main form of energy at the coast
A
Waves
21
Q
Factors affecting wave energy x3
A
-strength of the wind
-duration of the wind
-fetch of the wind
22
Q
How are waves formed
A
-air moves across the water
-friction form ripples or waves
-orbital circular motion of particles in the sea
-as waves hit the beach the circular motion is broken and they break on the shore
23
Q
Formation of constructive waves
A
Distant weather systems generate them in the open ocean
24
Q
Constructive wave form
A
Low, surging waves with a long wavelength
25
Constructive wave break
Strong swash, weak backwash
26
Constructive wave beach gain / loss
Beach gain
27
Constructive wave beach profile
Associated with a gentle beach profile - overtime they build up and make it steeper
28
Formation of destructive waves
Local storms
29
Destructive wave form
High, plunging waves with a short wavelength
30
Destructive wave break
Weak swash, strong backwash
31
Destructive wave beach gain / loss
Beach loss
32
Destructive wave beach profile
Associated with a steeper profile - overtime they flatten the beach
33
High energy coastline characteristics
-rocky
-erosion exceeds deposition
34
High energy coast example in the uk
Atlantic facing coasts e.g. Cornwall
35
High energy coastlines typical landforms
-headlands
-bays
-wave cut platforms
36
Low energy coastline characteristics
-sandy
-deposition exceeds erosion
37
Low energy coast example in the uk
Sheltered bays and estuaries e.g. Lincolnshire
38
Low energy coasts typical landforms
-beaches
-spits
-coastal plains
39
What is wave refraction
Distortion of wave fronts as they approach an indented shoreline
40
What does wave refraction cause
Energy to be more concentrated at headlands and dissipated at bays
41
What are tides
Changes in the water level caused by the gravitational pull of the moon
42
What is a tidal range
The difference between high and low tides
43
What affects the tidal range
Spring and neap tides
44
What does a tidal range so
High tidal range creates powerful tidal currents as tides rise and fall
45
Why are tidal currents important
Important transfer mechanisms in transporting sediment
46
How do rip currents form
Plunging waves cause a build up of water at the top of the beach and backwash is forced just below the surface of the breaking waves
47
What do rip currents do
Drag things into deeper water
48
Sources of sediment x6
-rivers
-cliff erosion
-longshore drift
-wind
-glaciers
-offshore sediment
49
Losses from the sediment budget
Deposition in sediment sinks
50
Gains to the sediment budget
Coastal erosion or sediment brought into the system
51
What is weathering
The breakdown of rocks at or near to the ground leading to the transfer or material
52
3 types of weathering
-mechanical
-chemical
-biological
53
Mechanical weathering
Break up of rocks without any chemical changes
54
3 types of mechanical weathering
-freeze thaw
-salt crystallisation
-wetting and drying
55
What is freeze thaw
-mechanical weathering
When water in a crack of a rock freezes and expands, widening the crack and breaking off rocks which fall to the base as scree
56
What is salt crystallisation
-mechanical weathering
When salt water evaporates and leaves salt crystals which exert stress and cause the rock to break up
57
What is wetting and drying
-mechanical weathering
When some rocks expand when wet and contract as they dry, causing them to crack and break up
58
Chemical weathering
Chemical reaction where salts may be dissolved or result in a clay like deposit which is easily eroded
59
3 types of chemical weathering
-carbonation
-oxidation
-solution
60
What is carbonation
-chemical weathering
When rainwater absorbs co2 from the air to form weak carbonic acid, which reacts with calcium carbonate in the rocks to form calcium bicarbonate which is easily dissolved
61
What is oxidation
-chemical weathering
When a reaction of minerals with oxygen occurs leaving rocks more vulnerable to erosion
62
What is solution
-chemical weathering
When rock minerals dissolve
63
Biological weathering
Breakdown of rocks by organic activity
64
3 types of biological weathering
-thin plant roots
-birds and animals
-marine organisms
65
What is thin plant root weathering
-biological weathering
When plant roots grow into small cracks and expand and exert force as they grow, breaking up the rock
66
What is bird and animal weathering
-biological weathering
When birds and animals dig burrows into cliffs
67
What is marine organism weathering
-biological weathering
When marine organisms burrow into rocks or secrete acids
68
What is mass movement
The downhill movement of material under the influence of gravity
69
Types of mass movements x7
-soil creep
-solifluction
-mudflow
-runoff
-landslide
-slump
-rockfall
70
Soil creep
-nature of movement
-rate of movement
-wet / dry
-flow
-gradual
-wet
71
Solifluction
-nature of movement
-rate of movement
-wet / dry
-flow
-gradual
-wet
72
Mudflow
-nature of movement
-rate of movement
-wet / dry
-flow
-rapid
-wet
73
Runoff
-nature of movement
-rate of movement
-wet / dry
-flow
-rapid
-wet
74
Landslide
-nature of movement
-rate of movement
- wet / dry
-slide
-rapid
-dry or wet
75
Slump
-nature of movement
-rate of movement
-wet / dry
-slide
-rapid
-dry or wet
76
Rockfall
-nature of movement
-rate of movement
-wet / dry
-fall
-rapid
-dry
77
What is soil creep
When particles rise towards the ground surface due to wetting or freezing and then return vertically to the surface in response to gravity as the soil dries out
78
What is solifluction
Similar to solid creep but specific to cold environment -> soil thaws in summer and gets oversaturated because it overlays impermeable permafrost. The active layer slowly moves downhill by a combination of heave and flow
79
What is a mudflow
The flowing downhill of earth and mud, often after heavy rainfall. The water gets trapped within the rock, forcing the rock particles apart, leading to slope failure
80
What is rockfall
The sudden breaking away of individual rocks at a cliff face, associated with steep cliffs and heavily jointed, resistant rock. Often triggered by mechanical weathering resulting scree is gradually removed by the sea
81
What is a landslide
A block of rock moving rapidly downhill, the moving block of material remains largely intact
82
What is a slump
Similar to a landslide but slide surface is curved rather than flat. Occurs where permeable rocks overlies impermeable rock which causes a build up of pore pressure
83
What is runoff
Links the water cycle and coastal system. Overland flow moves particles into the coastal zone, forming an input to the sediment cell. Transfers both water and sediment from one store to another
84
Why is coastal erosion important
Removes debris from the foot of cliffs and provides an input into coastal sediment cells
85
5 coastal erosion processes
-hydraulic action
-wave quarrying
-corrasion
-abrasion
-solution
86
What is hydraulic action
The compression and expansion of air forced into cracks in rock by wave pounding - continuous process causes rock to break off
87
What is wave quarrying
The scooping action of waves breaking against unconsolidated material such as sands and gravels
88
What is corrasion
Sand and pebbles are hurled by wave action at the cliff foot, chipping away at the rock
89
What us abrasion
A ‘sandpaper’ effect of waves dragging sediment up and down or across the shoreline, eroding and smoothing rocky surfaces
90
What is solution
Weak acids in seawater dissolve alkaline rock or the alkaline rock
91
Factors affecting coastal erosion x6
-waves = destructive waves at their most powerful
-rock type = tough, resistant rocks erode slower than clays and shales
-geological structure = cracks and joints create weaknesses in the cliff
-beach = absorb energy from the waves and protect the cliff
-subaerial processes = weathering and mass movement create debris that’s easily eroded
-coastal management = groynes and sea walls impact on sediment transfer and patterns of wave energy
92
Types of coastal transportation x4
-traction
-saltation
-suspension
-solution
93
What is traction
The rolling of coarse sediment across the seabed
94
What is saltation
Sediment being bounced along the seabed
95
What is suspension
Smaller sediment being picked up and carried with the flow of water
96
What is solution
Chemicals dissolved in the water and transported elsewhere
97
What is longshore drift
Transfer mechanism which moves vast amount of sediment
98
How does longshore drift work
-waves approach the beach at an angle carrying material up the beach
-backwash pulls material down the beach at a right angle to the coastline (due to gravity)
-continues along the coast
99
When does coastal deposition take place
When the velocity of the water falls below a critical value for a particular size of particle
100
Factors affecting cliff profiles and rate of retreat
-when do steep cliffs occur
-rock is strong and resistant
-sedimentary rocks dip steely or vertically
-no beach
-exposed coastline
-long fetch
-high energy waves
101
Factors affecting cliff profiles and rate of retreat
-when do gentle cliffs occur
-rocks are weak
-rocks dip towards the sea
-location is sheltered
-short fetch
-low energy waves
-wide beach
102
Formation of wave cut platform
-waves break against the cliff
-wave cut notch is created
-as the notch gets bigger, the cliff is undercut
-rock above becomes unstable
-collapses into the sea
103
Formation of caves, arches, stacks, stumps
-joints and faults are eroded by hydraulic actin and abrasion to form CAVES
-continues to erode through the rock forming an ARCH
-top of the arch collapses due to the gap becoming too big to form a STACK
-the stack gets eroded at the tide mark and the top collapses to form a STUMP
104
Landforms of coastal deposition x7
-beaches
-spits
-tombolos
-offshore bars
-sand dunes
-barrier beaches
-mudflats and salt marshes
105
What is a beach
Temporary store that extends from high tide to low tide
106
When does beach accretion take place
During prolonged periods of constructive waves driven by storms hundreds of miles away
107
What are swash aligned beaches
Beaches facing into the prevailing wind direction where sediment moves up and down with little lateral transfer
108
What are drift aligned beaches
Beaches side-on to the prevailing wind direction where sediment is transferred along the coast by longshore drift
109
What are spits
Long, narrow features made of sand or shingle that extends from the land into the sea
110
Where do spits form
Drift aligned beaches
111
What are tombolos
A beach between a small island and the mainland
112
What are offshore bars
Submerged or partly exposed ridges of sediment created by offshore waves
113
What are sand dunes
Large quantities of sand that sit on sandy beaches
114
What do sand dunes need to form
-large quantities of sand from constructive waves
-large tidal range, creating a large exposure of sand that can dry at low tide
-dominate onshore winds, to blow dried sand to the back of the beach
115
Types of sand dunes x6
-embryo dune = smallest dune closest to the sea
-fore dune = slightly bigger
-yellow dune = bigger and further back
-grey dune = bigger again
-dune slack = dip between surfaces where water collects
-mature dune = biggest dune at the back of the beach
116
Characteristics of embryo dunes
-sand is continuously moving
-high PH = over 8
-high wind speeds
-lots of salt spray
-no more than 1 metre high
-80% of sand is exposed
117
Characteristics of fore dunes
-drought resistance plants colonise
-Lyme grass and marran grass
-more sand gets trapped and dunes grow
-20% sand is exposed
118
Characteristics of yellow dunes
-greater diversity of plants
-humus layer builds up
-PH slightly alkaline
-more sheltered
-less salt spray
-marran grass dominates
-dunes are 5-10 meters high
-80% sand is vegetated
119
Characteristics of grey dunes
-stable
-100% vegetated
-less marran grass and more sea splurge
-50-100 meters from the sea
-sheltered from the wind
-humus darkens allowing soil to form
-PH is more acidic
-water contents low
120
Characteristics of a dune slack
-found between mature dunes where the water table reaches the surface
-plants adapt to dampness
-rushes, cotton grass, creeping willow
-can get peaty soil
121
Characteristics of mature dunes
-found 100+ metres from the shore
-if undisturbed, can support shrubs and trees
-humans plant fast growing conifers
122
Formation of sand dunes
-sand deposited by constructive waves
-long tidal range to ensure dryness
-dry sand gets blown by onshore winds
-piece of debris catches the sand as it moves by saltation
-dune grows around the debris
-grow through the process of succession
123
What are barrier beaches
Where a beach or spit extends across a bay to join two headlands
124
What are lagoons
Water trapped behind a barrier beach
125
What are mudflats and salt marshes
Areas of flat, silty sediments that accumulate around estuaries or lagoons
126
3 types of environment where mudflats -> salt marshes occur
-sheltered ares where deposition occurs
-where salt and freshwater meets
-where there are no strong tides or currents to prevent sediment deposition and accumulation
127
2 main causes of sea level change
-eustatic change
-isostatic change
128
What is eustatic change
-where the sea level itself rises and falls
-global changes
-in glacial periods, water that is usually held in oceans is stored in ice sheets = sea level falls
-when ice sheets melt their stored water flows into rivers and oceans = sea level rises
129
What is isostatic change
-the land itself rises or falls relative to the sea
-occurs locally
-glacial periods causes the land to sink due to the weight
-ice melts reduces the weight on the land causing it to rise
130
Landforms caused by sea level changes
-a fall in sea level exposes land previously covered by the sea, creating an emergent coastline
-a rise in sea level floods the coast and creates a submergent coastline
131
Emergent coastline landforms
-raised beaches
-relict cliffs
-wave cut platforms
132
Formation of raised beaches
-sea levels fall and rise during glaciation
-causes erosion and sediment deposition
-land is uplifted by tectonic activity
-beaches become elevated about sea level
133
Formation of relict cliffs
-marine erosion
-above the tide
-when the land rebounds following an ice age
134
Formation of wave cut platforms
-platform is broadened as waves erode
-notch at the cliff base causes overhanging rock to fall
-sea levels drop exposing the wave cut platforms
135
Submergent coastline landforms
-rias
-fjords
-Dalmatian coasts
136
What are rias
Sheltered, winding inlets formed when a rise in sea level drowned river valleys
137
What are fjords
Long, steep sided troughs
138
What are Dalmatian coasts
Exposed tops of ridges form a series of offshore islands running parallel to the coast
139
Formation of rias
-rising sea levels flood narrow, winding inlets and river valleys
140
Formation of fjords
-rising sea levels flood deep glacial valleys to create natural inlets and harbours
141
Formation of Dalmatian coastlines
-valleys running parallel to the coast become flooded as a result of sea level rise
-leading a series of narrow, long and rugged islands
142
2 types of human intervention at the coast
-hard engineering
-soft engineering
143
Hard engineering strategies x5
-groynes
-sea walls
-rock armour
-revetments
-offshore breakwater
144
What are groynes
Timber structures built perpendicular to the coastline that trap sediment being moved by LSD
145
Advantages of groynes x3
-works with natural processes to build up the beach
-increases tourist potential
-relatively cheap
146
Disadvantages of groynes x2
-starves beaches further along the coast
-unnatural and unattractive
147
What are sea walls
Stone or concrete walls at the foot of a cliff or the top of beaches
Usually have a curved face to reflect the waves back to the sea
148
Advantages of sea walls x2
-effective
-give somewhere for people to walk
149
Disadvantages of sea walls x3
-reflect wave energy rather than absorbing it
-unnatural
-very expensive
150
What is rock armour
Large rocks at the foot of a cliff or top of a beach
Forms a permeable barrier to the sea that absorbs wave energy
151
Advantages of rock armour x1
-relatively cheap and easy
152
Disadvantages of rock armour x2
-intrusive
-dangerous to people
153
What is revetments
Sloping rock structures placed at the foot of a cliff or top of a beach to break up wave energy
154
Advantages of revetments x1
-relatively cheap
155
Disadvantages of revetments x2
-unnatural
-high levels of maintenance
156
What are offshore breakwaters
Partly submerged rock barrier made to break up the waves
157
Advantages of offshore breakwater x1
-effective
158
Disadvantages of offshore breakwater x2
-unattractive
-navigation hazard
159
Soft engineering strategies x5
-beach nourishment
-dune regeneration
-managed retreat
-land-use management
-do nothing
160
What is beach nourishment
Beaches are made higher and wider by importing sand and shingle to an area affected by LSD
161
Advantages of beach nourishment x3
-cheap
-natural appearance
-effective
162
Disadvantages of beach nourishment x3
-increases erosion elsewhere
-affects the marine ecosystem
-large storms increase the cost of
163
What is dune regeneration
Building up of dunes and increasing vegetation to help strengthen the dunes and prevent retreat
164
Advantages of dune regeneration x3
-provides a barrier
-cheap
-increases biodiversity
165
Disadvantages of dune regeneration x2
-temporary fencing
-easily damaged
166
What is managed retreat
Areas of the coast are allowed to erode
167
Advantages of managed retreat x2
-retains the natural balance
-encourages the development of beaches
168
Disadvantages of managed retreat x2
-people lose their livelihood (land)
-compensation will be needed
169
What is land-use management
Controlling and restricting building in areas at risk of coastal erosion or flooding
170
Advantages of land-use management x3
-prevents future damage
-encourages sustainable land use
-reduces costs
171
Disadvantages of land-use management x2
-hard to implement in developed areas
-doesn’t protect existing infrastructure
172
What is do nothing
Allowing natural processes to take place without intervention
173
Advantages of do nothing x3
-no direct costs
-allows natural landscapes
-ecosystems can evolve
174
Disadvantages of do nothing x3
-high risk property damage
-unpopular with communities affected
-loss of habitats
175
Shoreline management plans (SMP)
Based on the principle that intervention will have knock-on effects outside each cell
176
Four options of SMP
-hold the line
-advance the line
-managed retreat
-do nothing
177
SMP - hold the line
Maintaining the current coastline
178
SMP - advance the line
Extending the coastline out to sea
179
SMP - managed retreat
Allowing the coastline to retreat in a managed way
180
SMP - do nothing
Letting nature take its course
181
Integrated coastal zone management (ICZM)
-what does it do
Brings together all the stakeholders involved in the development, management and use of the coast in order to manage the coastal environment based on natural process and the coastal system
182
ICZM impacts
Complete sections of the coast are managed holistically, enabling sustainable measures to be implemented based on natural process and the coastal system
183
SMP aims x6
-promote long term management
-asses the risk associated with coastal evolution
-address risks in sustainable ways
-ensure management plans are eco-friendly
-assess risk to developed, natural and historical areas
-provide policy for coastal management
184
Basic plan for SMP
Provides a strategic approach to managing coastal areas
185
Basic plan for ICZM
Promotes sustainable management of coastal zones by integrating environmental, economic and social objectives
Physical Geography
flashcards
Decks in class (20)
# Cards
-
Volcano hazards37
-
Hazards key terms46
-
Japan Tsunami CS4
-
Indonesia Tsunami CS4
-
Eyjafjallajokull Eruption CS6
-
Maldives Sea Level Rise Coasts CS6
-
Coasts185
-
Odisha’s Coast CS14
-
Slapton Coast CS47
-
Turkey-syria Earthquake CS7
-
Hurricane Sandy CS8
-
Australian Wildfire CS9
-
Typhoon Haiyan CS9
-
Plate Boundaries13
-
Odisha Coasts (use For Now)19
-
Water And Carbon Cycle77
-
Philippines As A Multi-hazardous Area9
-
Caracas4
-
Amazon Rainforest5
-
Pickering Beck5
