Coasts Flashcards

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1
Q

The littoral zone

A

The wider coastal zone
Includes adjacent land areas and shallow parts of the sea just offshore
Cliff, FS, BS, OS, NS

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2
Q

Cliff profile

A

The height and angle of a cliff face as well as its features such as wave-cut notches or changes in slope angle

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3
Q

Coastal accretion

A

The deposition of sediment at the coast and the seaward growth of the coastline, creating new land
Often involves sediment deposition being stabilised by vegetation

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4
Q

Dynamic equilibrium

A

The balanced state of a system when inputs and outputs balance over time
If one element in the system changes because of an outside influence, the internal equilibrium is upset and other components change
Through feedback, the system adapts to change and the equilibrium is regained

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5
Q

Faults

A

Major fractures in rock produced by tectonic forces and involving the displacement of rocks on either side of the fault line

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6
Q

Holocene

A

The geological epoch that began about 12,000 years ago at the end of the last Pleistocene ice age
Early stages were marked by sea level rises of about 35m and a warming interglacial climate

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7
Q

Unconsolidated sediment

A

Material such as sand, gravel and clay and silt that has not been compacted and cemented to become sedimentary rock (has not undergone lithification) so it is easily eroded as it is loose

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8
Q

Pore water pressure

A

The pressure water experiences at a particular point below the water table due to the weight of the water above it

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9
Q

Swash

A

The flow of water up a beach as a wave breaks

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10
Q

Backwash

A

When water runs back down the beach to meet the next incoming wave

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11
Q

Fetch

A

The uninterrupted distance across water over which a wind blows, and therefore the distance waves have to grow in size

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12
Q

Beach morphology

A

The shape of a beach, including its width and slope (the beach profile) and features such as berms, ridges and runnels
It also includes the type of sediment (shingle, sand and mud) found at different locations on the beach

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13
Q

Blow hole

A

Forms when a coastal cave turns upward and breaks through the flat cliff top
Usually because of erosion especially at weak strata or the presence of a fault line

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14
Q

Currents

A

Flows of seawater in a particular direction driven by winds or differences in water density, salinity or temperature
Some are almost continuous, the global thermohaline circulation
Others more sporadic e.g. longshore currents
Some for hours e.g. rip currents

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15
Q

Mass movement

A

The downslope movement of rock and soil; it is an umbrella term used for a wide range of specific movements including a landslide, rockfall and rotational slide

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16
Q

Isostatic change

A

A local rise or fall in the land level

17
Q

Eustatic change

A

Involves a rise or fall in water level caused by a change in volume of water
This is a global change
Affecting all the world’s connected seas and oceans

18
Q

Accretion

A

This occurs when sediment is added to a landform, such as a river delta, by deposition. It can be built up to form new land, allowing a delta to grow out to sea
It tends to balance the subsidence caused by the weight of the newly deposited sediment

19
Q

Post-glacial isostatic adjustment

A

Refers to the uplift experienced by land following the removal of the weight of the ice sheets
Often called post-glacial rebound or post-glacial readjustment

20
Q

Ria

A

A drowned river valley in an unglaciated area caused by sea level rises flooding the river valley, making it much wider than would be expected based on the river flowing into it

21
Q

Barrier islands

A

Offshore sediment bars, usually sand dune covered but, unlike spits, they are not attached to the coast
Foud 500km to 30km offshore and can be tens of KM long

22
Q

Dredging

A

Involves scooping or sucking sediment up from the seabed or a river bed, usually for construction sand or gravel or to deepen a channel so that large boats can navigate it

23
Q

Dissipation

A

Describes how the energy of a wave is decreased by friction with beach material during the wave swash up the beach
A wide beach slows waves down and saps their energy, so when they break most of the energy is gone

24
Q

Megaproject

A

A very expensive (over US$1 billion) technically difficult and usually long-term engineering project
Many mega projects have multiple aims and often large environmental impacts

25
Q

Return period

Recurrence interval

A

Refers to the frequency of a flood of a particular magnitude
a 1:100 flood event will occur on average every 100 years
There is a one per cent chance of that flood occurring in a given year

26
Q

Environmental refugees

A

Communities forced to abandon their homes due to natural processes including sudden ones, such as landslides or gradual ones such as erosion or rising sea levels

27
Q

Sustainable coastal management

A

Managing the wider coastal zone in terms of people and their economic livelihoods, social and cultural wellbeing and safety from coastal hazards, as well as minimising environmental and ecological impacts

28
Q

Conflict

A

In the context of coastal management, conflict is disagreement over how the coast should be protected
Conflict exists between different stakeholders such as residents vs. the council

29
Q

Littoral cells

Sediment cells

A

All coastlines divide up into littoral cells containing sediment sources, transport paths and sinks
Each littoral cell is isolated from adjacent cells and can be managed as a holistic unit

30
Q

Outflanking

A

When erosion gets behind coastal defences at the point where they stop which leads to rapid erosion inland and undermining of defences