Coasts Flashcards
1
Q
System
A
a group of interrelated parts that work together and are connected by flows or transfers of energy, material, or matter.
2
Q
Open system
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Open systems are when systems receive inputs and transfer outputs of energy or matter with other systems.
3
Q
Closed system
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Closed systems only have energy as their input and output; matter is contained within the system boundary.
4
Q
Inputs
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Where matter or energy is added to the system.
5
Q
Outputs
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Where matter or energy leaves the system.
6
Q
Store
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Where matter or energy builds up in the system.
7
Q
Flows
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Where matter or energy moves in the system.
8
Q
Equilibrium
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a state of balance within systems where inputs and outputs are equal and processes operate to maintain the balance.
9
Q
Dynamic equilibrium
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A state of balance within a natural system where inputs and outputs are equal despite ongoing changes and processes.
10
Q
Wind
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Air which moves in a particular direction.
11
Q
Prevailing wind
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The most frequent wind direction a location experiences.
12
Q
Fetch
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the distance that wind blows across a body of water before it reaches the coast.
13
Q
Constructive waves
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low-energy waves that build up beaches. They have a longer wavelength and a lower frequency than destructive waves, meaning they are less frequent and further apart. A key characteristic is that their swash is stronger than their backwash.
14
Q
Destructive waves
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high-energy waves characterized by a strong backwash that erodes coastlines. They are typically associated with stormy weather and have a short wavelength, breaking frequently on the shore.
15
Q
Wave refraction
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the bending of waves as they approach an irregular coastline, causing their energy to be concentrated or dispersed.
16
Q
Tides
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the regular rise and fall of sea levels caused by the gravitational pull of the moon and, to a lesser extent, the sun.
17
Q
Currents
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the steady, directional movement of a fluid within a larger body of that fluid.
18
Q
Sediment budget
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the balance between the inputs and outputs of sediment within a defined coastal system (like a sediment cell) over a specific time period
19
Q
Sediment cell
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a self-contained section of coastline where sediment movement is primarily confined within its boundaries.
20
Q
Sources
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the origins of solid particles (like rock fragments, sand, and shells) that are transported and deposited within a coastal or river system.
21
Q
Transfer
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the movement of sediment from one location to another within a sediment cell, or between different sediment cells.
22
Q
Sink
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locations within a sediment cell where deposition dominates, leading to the accumulation and storage of sediment.
23
Q
Erosion
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the process by which land surfaces are worn away and materials are transported from one place to another by natural forces like wind, water, or ice.
24
Q
Hydraulic action
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the erosive power of water when it impacts a surface, like a river bank or cliff face. The force of the water pushes air into cracks in the rock, compresses the air, and then the sudden release of pressure causes the rock to weaken and break apart.
25
Abrasion
the process of erosion where loose rock and sediment are carried by water, wind, or ice, and then scraped or ground against a hard surface (like a rock face or riverbed), wearing it away. This "sandpaper" effect smooths and shapes the surface over time.
26
Attrition
the erosion process where rocks and pebbles carried by waves or rivers collide, causing them to wear down and become smaller and more rounded over time.
27
Solution (erosion)
the dissolving of rocks by water, particularly in coastal or river environments. This process is most common with alkaline rocks like limestone and chalk, as the slightly acidic nature of seawater or river water can cause them to dissolve. The dissolved rock material is then carried away, contributing to the erosion of the coastline or riverbed.
28
Traction
the process of large, heavy rock particles (like boulders and cobbles) being rolled along the river or sea bed by water flow.
29
Saltation
a mode of sediment transportation where smaller particles, like pebbles or sand, are bounced along a river or seabed by the force of flowing water.
30
Suspension
the process where fine sediment, like silt and clay, is carried within the water flow, rather than being rolled or bounced along the river bed or sea floor. This means the particles are lifted and held up by the water's current.
31
Solution (transport)
the process where dissolved minerals, often from soluble rocks like limestone or chalk, are carried by a river or sea.
32
Long-shore drift
the movement of sediment (sand, shingle, and pebbles) along a coastline by the action of waves and currents. It's primarily driven by waves approaching the shore at an angle, causing a zig-zag movement of material along the beach.
33
Deposition
the process where material, like sediment or minerals, is dropped or laid down by a natural agent, such as wind, water, or ice, when its energy decreases. This can lead to the formation of various landforms.
34
Weathering
the breakdown of rocks in situ, meaning in place, at or near the Earth's surface. This process doesn't involve the removal of the rock material, but rather its disintegration and decay.
35
Mechanical weathering
the breakdown of rocks into smaller pieces through physical processes, without altering their chemical composition. This process is driven by forces like temperature changes, wind, water, and biological activity, causing rocks to fracture and fragment.
36
Freeze thaw weathering
a form of mechanical weathering where water freezes and expands within cracks in rocks, causing them to widen and eventually break apart. This process is particularly effective in cold climates where temperatures regularly fluctuate around freezing.
37
Chemical weathering
the breakdown of rocks due to chemical reactions, altering their chemical composition rather than just breaking them into smaller pieces. This process is primarily driven by the interaction of rainwater, often slightly acidic due to dissolved carbon dioxide, with minerals within the rock.
38
Carbonation
a type of chemical weathering where rainwater, slightly acidic due to dissolved carbon dioxide (CO2) in the atmosphere, reacts with carbonate rocks like limestone. This reaction dissolves the rock, creating soluble calcium bicarbonate, which is then carried away in solution by water.
39
Hydrolysis
a type of chemical weathering where water reacts with minerals in rocks, changing their chemical composition and making them more susceptible to breakdown. This reaction typically leads to the formation of new clay minerals and soluble salts.
40
Biological weathering
the breakdown of rock in situ (on its original location) by the actions of living organisms. This process often involves plant roots growing into cracks, widening them and causing rock fragments to break away. It can also include animal activity like burrowing, or the effects of microorganisms
41
Mass movement
the downslope movement of soil, rock, and other debris under the influence of gravity.
42
Rockfall
The downward movement of individual rock fragments or blocks due to gravity, often triggered by weathering or other geological processes.
43
Landslide
a mass movement of rock, soil, and/or debris downhill, often triggered by factors like heavy rainfall, earthquakes, or human activities.
44
Mudflow
Mudflows are a type of mass movement where soil and debris, saturated with water, flow rapidly down a slope.
45
Slumping
a type of mass movement where a large block of material (like clay or soil) rotates down a slope, often along a concave slip plane.
46
Rotational slip
a type of mass movement, specifically a slump, where saturated soil or rock debris moves downhill along a curved or concave plane, causing a rotational movement. This process often leaves behind a curved scar on the cliff face and is particularly common at coastal areas with weaker rock types like clay.
47
Cliff
a steep, vertical, or near-vertical rock face that borders a coastline or riverbank.
48
Wave cut platform
the narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or sea that was created by erosion. Wave-cut platforms are often most obvious at low tide when they become visible as huge areas of flat rock.
49
Headland
a point of land that extends out into a body of water, typically surrounded by water on three sides. It is often characterized by steep cliffs or hills and is formed from hard, erosion-resistant rock like chalk, limestone, or granite.
50
Bay
a crescent-shaped or semi-circular inlet of the sea or ocean, where the land curves inwards, typically between two headlands. These areas are usually sheltered and characterized by lower energy wave conditions, often leading to the formation of beaches.
51
Cave
a natural, open-air cavity in the earth's surface, large enough to allow human entry. These formations can occur in various rock types and are formed by a range of geological processes, often related to erosion and weathering.
52
Arch
a coastal erosional landform formed when waves erode through a headland, creating a natural passage. This process begins with the formation of a cave, which is widened and deepened until it cuts through the headland, leaving behind an archway.
53
Stack
an isolated pillar of rock that remains after the top of a coastal arch has collapsed. This process typically occurs when a cave is eroded through a headland, forming an arch, and the unsupported top collapses due to erosion and gravity. The stack then stands detached from the headland.
54
Stump
the final stage in the erosional sequence of coastal landforms, specifically the remnants of a collapsed stack.
55
Geo
a narrow, steep-sided inlet in a coastal cliff, typically formed by wave erosion along a line of weakness like a joint or bedding plane.
56
Blowholes
a coastal landform, typically a vertical shaft, formed when a cave roof collapses, allowing water and air to be forcefully ejected during wave action. It's essentially a chimney-like structure that can be seen on the cliff face, often above a cave, and is formed through erosion and weathering processes.
57
Beaches
a depositional landform, an accumulation of sediment (sand, shingle, pebbles) between the high and low tide levels, formed when waves deposit eroded material along the coast.
58
Spits
a depositional landform, a long, narrow beach of sand or shingle that extends out into the sea, connected to the mainland at only one end. It forms when longshore drift, the process of sediment moving along a coastline, encounters a change in the coastline's direction, such as at a river mouth or a bay. The deposited material builds up, creating the spit.
59
Bar
a ridge of sand or shingle that extends across a bay and connects two headlands, effectively enclosing a body of water behind it to form a lagoon.
60
Tombolo
a coastal landform, specifically a sandbar or spit, that connects an island to the mainland or another island. It's formed when a spit extends from the mainland or an island, connecting it to a nearby landmass. This connection is typically a narrow strip of land, often composed of sand or shingle.
61
Cuspate forelands
a triangular, low-lying headland formed by the deposition of sediment, typically sand and shingle, along a coastline. These features are created when longshore drift from opposing directions converges, depositing material to form a triangular shape.
62
Sand dune
a hill or ridge of sand formed by wind or waves, primarily found on beaches or in deserts. They are dynamic landforms that shift and change over time due to wind patterns and vegetation growth.
63
Sand dune succession
the process by which a sand dune ecosystem develops over time. It's a form of primary succession where pioneer species (like marram grass) colonize initially barren sand and gradually modify the environment, allowing other species to establish. This leads to a gradual change in the vegetation community until a stable climax community develops.
64
Embryo dune
the earliest stage of sand dune formation. These are the smallest, youngest dunes, typically only a few meters tall, located at the back of a beach where sand starts accumulating. They are often characterized by minimal vegetation, with pioneer species like lime grass or sea couch grass starting to colonize and stabilize the sand.
65
Foredune
Foredunes are the seaward-most line of coastal dunes and are typically formed by sand accumulating and being trapped by vegetation.
66
Yellow dune
a sand dune that is close to the beach and is characterized by its light yellow color and loose, mobile sand. These dunes are the first to form in a sand dune succession and are dominated by pioneer vegetation like Marram grass.
67
Grey dune
a stable, older sand dune that's further inland from the beach compared to younger, more mobile yellow dunes. They're characterized by a darker, greyish color due to the accumulation of humus and a continuous cover of vegetation, including lichens.
68
Duneslack
a depression or low-lying area found between sand dunes, often seasonally flooded and with low nutrient levels. These slacks form due to wind erosion, where sediment is removed from the leeward base of one dune ridge and the windward side of the next.
69
Salt marsh
a coastal wetland area where salt-tolerant plants thrive on muddy shores, regularly flooded and drained by tides. They are found in sheltered bays and estuaries, between land and open water, and are characterized by their salt-resistant vegetation.
70
Cuspate foreland
a triangular, low-lying landform, typically made of sand and gravel, that extends outwards from a shoreline. It's formed when longshore drift currents from opposing directions converge, depositing sediment and creating a triangular shape.
Elaboration:
Formation:
Cuspate forelands arise when longshore drift, the movement of sediment along a coastline, is driven by two different wind directions or currents converging at a point. This convergence leads to the deposition of sediment, building up a triangular landform.
Characteristics:
These landforms are characterized by their triangular shape, low elevation, and extension from the shoreline into the sea. They can range in size from a few meters to several kilometers in length.
Examples:
A well-known example of a cuspate foreland is Dungeness in Kent, UK, which shelters Romney Marsh. Other examples can be found along lakeshores, such as Point Pelee on Lake Erie.
Significance:
Cuspate forelands can provide important habitats for various species of flora and fauna. They can also act as a natural defense against erosion and storm surges, sheltering areas behind them. However, they are also vulnerable to changes in sediment supply and sea-level rise, according to the ArcGIS StoryMaps.
71
Mudflats
where fine sediments, such as silt and clay, are deposited. These flats are exposed at low tide and submerged at high tide, making them part of the intertidal zone. Mudflats are characterized by their flat, muddy surfaces and are often crisscrossed by channels.
72
Delta
a depositional landform that forms at the mouth of a river where it flows into a body of water with lower energy, like a sea or lake. Rivers slow down and lose energy, causing them to deposit the sediment they've been carrying. This deposited sediment builds up to form the delta, which is often triangular in shape.
73
Hard engineering
using artificial structures, like seawalls and breakwaters, to control coastal processes and protect against erosion and flooding.
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Sea wall
A structure built along a coastline to protect against coastal erosion and flooding. It acts as a barrier, either deflecting waves back to sea or absorbing their energy, thus preventing them from reaching land and causing damage.
75
Groynes
a long, narrow structure built out from the beach at a right angle to the coast, designed to trap sediment and reduce the impact of wave action.
76
Rock armour (rip rap)
large boulders or rocks placed at the foot of cliffs or along a beach to absorb and dissipate wave energy, thus reducing erosion.
77
Gabions
that uses a mesh cage filled with rocks or boulders to protect against erosion. These structures are designed to absorb wave energy and prevent the destruction of the coastline.
78
Revetments
sloping, hard engineering structures built along coastlines to protect land from erosion and flooding. They are often made of concrete, stone, or timber and are designed to absorb wave energy, preventing it from damaging the shore.
79
Offshore breakwaters
a coastal engineering structure, typically made of rocks or concrete, built in the sea parallel to the coastline to protect the shore from wave action and erosion.
80
Soft engineering
the use of natural and nature-based methods to manage coastal erosion and flooding.
81
Beach nourishment
the artificial addition of sand or other sediment to a beach to increase its size and height. This process is often used to counteract erosion and provide protection against storm surges and flooding. It can also be used to maintain or improve a beach's recreational value.
82
Dune regeneration
the creation or restoration of sand dunes, often involving planting vegetation like marram grass to stabilize the sand and prevent erosion.
83
Shoreline management plan (SMP)
a strategy for managing flood and erosion risks along a specific stretch of coastline, considering short, medium, and long-term perspectives. It identifies the best ways to protect people, developed areas, historic sites, and natural environments from coastal hazards, while also identifying opportunities to improve shoreline management practices.
84
Managed retreat
a coastal management strategy where the shoreline is allowed to move inland, rather than being actively defended against the sea.
85
Hold the line
a strategy of maintaining the current position of the coastline by implementing coastal defenses to prevent further erosion or flooding.
86
Advance the line
extending the coastline further into the sea, typically by building new coastal defenses or reclaiming land.
87
Managed realignment
intentionally allowing a coastline to move inland to a new, more sustainable position. This is often done by removing existing coastal defenses, breaching seawalls, or relocating infrastructure.
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"do nothing"
a coastal management strategy where no active intervention or coastal defense is implemented, allowing natural processes like erosion and flooding to continue.
89
Cost benefit analysis
a tool used to evaluate the economic feasibility of a project or policy, often related to coastal management or environmental issues. It involves comparing the projected costs and benefits of a decision to determine if the benefits outweigh the costs.
90
Eustatic sea level change
global variations in sea level due to changes in the volume of water in the oceans.
91
Isostatic sea level change
changes in the level of the land relative to the sea, rather than changes in the actual volume of water in the ocean. This means the sea level appears to rise or fall locally as the land rises or sinks.
92
Emergent coastlines
formed when the relative sea level falls, either due to a decrease in sea level itself or an uplift of the land. This results in land that was once underwater being exposed, often leaving behind distinct landforms that reflect previous sea levels.
93
Raised beaches
These are flat, sandy or pebbly platforms that were once wave-cut platforms at the edge of the sea. They are now located above the current sea level, indicating a fall in sea level.
94
Relic cliffs
These are cliffs that were formed by marine erosion but are now above high tide level. They may have features like wave-cut notches, caves, and arches.
95
Submergent coastline
a coastline formed when sea levels rise, causing previously dry land to become submerged.
96
Rias
These are long, narrow inlets with a V-shaped cross-section, formed when river valleys are flooded by rising sea levels.
97
Fjords
These are long, narrow, deep inlets with steep sides, formed when glacial valleys are flooded. They are U-shaped, have a relatively straight profile, and can be deeper than the surrounding sea.
98
Dalmation coastline
a type of concordant coastline characterized by long, narrow islands running parallel to the shoreline and separated by narrow channels. These features are formed when sea levels rise, flooding pre-existing river valleys that are aligned parallel to the coast, leaving behind ridges as islands.
99
Concordant coastline
occurs when rock strata (layers of rock) run parallel to the coast, rather than at an angle to it. This alignment results in fewer headlands and bays compared to discordant coastlines where rock layers run perpendicularly to the coast.
100
Discordant coastline
alternating bands of hard and soft rock that run perpendicular (at a 90-degree angle) to the coastline. This arrangement leads to the formation of bays and headlands due to the different rates of erosion of the hard and soft rock types.
