Physical Landscape Flashcards

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1
Q

Definition of solution

A

Materials dissolved in water

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2
Q

Definition of suspension

A

Sand suspended in water

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3
Q

Definition of Traction

A

Rolling boulders

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4
Q

Definition of saltation

A

Bouncing pebbles

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5
Q

Definition of freeze-thaw weathering

A

Water enters a crack, freezes and expands by 10%, when it thaws, more water can enter the crack and so the process continues.

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6
Q

Definition of abrasion

A

Process where Sand/pebbles in waves rub against the coastline and smooth the surface

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7
Q

Definition of hydraulic action

A

Waves trap air in cracks in rocks, compressing the air and causing cavitation which expands the crack

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8
Q

Definition of corrasion

A

Large boulders thrown against the cliff face by the waves

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9
Q

Definition of carbonation

A

Acids in water dissolved minerals in the rock

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10
Q

How do waves form

A

Friction from wind blowing over the sea causing ripples that develop into waves

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11
Q

Definition of fetch

A

It is the distance that wave-generating winds blow across the open water

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12
Q

Why do waves break

A

As the gradient of the seafloor increases, friction slows the bottom of the wave which causes the crest of the wave to move faster and rise up

(Friction with seabed distorts circular motion, increasingly elliptical orbit as water becomes shallower)

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13
Q

Definition of mass movement

A

Downward movement or sliding of minerals under the influence of gravity

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14
Q

Key characteristics of constructive waves

A

Wave crests are far apart
Gently sloping front
Strong swash

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15
Q

Key characteristics of destructive waves

A

Waves are close together
Steep front
Strong backwash

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16
Q

What is a seawall

A
  • they are at the foot of cliffs/top of beach
  • high maintenance
  • £10 million per km
  • 3-5 metres high
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17
Q

What are groynes

A
  • prevents sediment from being moved down the beach by long-shore drift
  • £5000 per metre
  • causes higher erosion elsewhere downdrift
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18
Q

What are Rock armour

A
  • rocks against the cliff which forces waves to break therefore absorbing the waves energy
  • rocks are expensive to transport
  • £1000-£4000 per metre
  • obtrusive
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19
Q

What are gabions

A
  • Metal cages filled with rocks
  • unattractive
  • easy to maintain and last long
  • £2000 per metre
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20
Q

What is beach nourishment

A
  • where they build up a beach with sediment from nearby so it blends in
  • £3000 per metre
  • needs constant maintenance
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21
Q

Dune regeneration

A
  • it is where marram Grass is planted because Dunes are effective buffers for waves and then fenced off so they can grow
  • £20 per metre
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22
Q

What is Marsh creation

A
  • allowing low-lying coastal areas to be flooded
  • creates habitats
  • compensation is given for land so can be expensive
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23
Q

Definition of a drainage basin

A

An area of land drained by a river and its tributaries

24
Q

Definition of the source

A

The start of a river

25
Q

Definition of the mouth

A

The end of the river, usually where a river joins the sea

26
Q

Definition of a tributary

A

A small stream that joins a larger river

27
Q

Definition of a confluence

A

Where a tributary joins a larger river

28
Q

Definition of a watershed

A

It is a drainage basin and all the water in the area drains into one body of water

29
Q

What is a floodplain

A

They are wide, flat areas on either side of the river in its middle and lower course. They are created by migrating meanders and floods depositing layers of silt to form alluvium

30
Q

Definition of discharge

A

Quantity of water that passes a given point in a stream or river bank within a given period of time, measured in cumecs

31
Q

Characteristics of the upper course

A
  • steep, narrow valleys called V shaped Valleys
  • narrow, shallow river, looks fast flowing as areas of rapids
  • interlocking spurs
32
Q

Characteristics of the middle course

A
  • wider valleys
  • decreased gradient of landscape
  • meanders, oxbow lake, pools and riffles
33
Q

Characteristics of the lower course

A
  • Side of the valley is called the bluff
  • flooding occurs across this valley leaving ‘alluvium’ on valley floor
  • levees, estuary, delta
34
Q

Formation of a waterfall and gorge

A
  • occur when the river flows over resistant rock and then less resistant rock
  • see diagram
35
Q

What is LAG

A

The time between water landing on the Earth surface and entering a River channel

36
Q

Causes of flooding both physical and human

A

Physical:

  • precipitation
  • rapid thawing
  • silting of river channel (shallower)

Human

  • urbanisation (impermeable surfaces)
  • deforestation (reduces interception)
37
Q

Hard engineering for managing floods

A

Dams
Channel straightening
Embankments
Flood relief channels

38
Q

Soft engineering for managing floods

A

Wetlands (flood storage)
Floodplain zoning
River restoration

39
Q

Preparing for floods

A

Monitoring (satellites), environment agency warnings, individual planning (sandbags).

40
Q

Outline datchet objections to the Jubilee flood management scheme

A
  • public expense (moving railway and M4)
  • cheaper solutions
  • it will allow more floodplain development and could become stagnant and mosquito infested
  • increased flood risk to Datchet and Staines
  • noise and distruption (construction)
41
Q

Facts about Jubilee food management scheme

A
  • cost environmental agency £110 m.
  • first used in January 2003 but some banks failed at only 60% full, costing £3.5 m to repair.
  • environment agency said that it protected 400 properties from flooding and disruption was prevented to a further 1000.
  • villages east of the confluence e.g. Datchet, were flooded - some residents believe they were worse off.
42
Q

What facts are there for building the Jubilee flood management scheme

A
- Thames flooding has return periods
Normal cumecs = 60
Every 4-6 years = 350
Every 60 years = >500
Every 100 years = >600
- A flood is scheduled soon
  • more people now live on the flood plain
  • climate change may make floods more frequent/worse
  • River could be a nature reserve and recreation facility
43
Q

Evidence for worse conditions in Datchet

A
  • 2 river channels means it flows faster through the area than if it flooded before Datchet
  • between Thames and Jubilee river there is agricultural land which is being protected instead of residential land
44
Q

How did the Jubilee scheme work in 2003

A
  • 144 cumecs flowed in Jubilee river only 60% of designed capacity (full = 215 cumecs)
  • allowed Thames to be 260 cumecs instead of 404 cumecs
45
Q

Does the Jubilee river have enough capacity

A
  • many are unconvinced
  • 2014, with Jubilee river, Thames still flooded
  • claims to hold 285 cumecs but was damaged at 144
46
Q

Concluding comments on the Jubilee river

A

2014 showed the area will still flood but Jubilee clearly limited impacts on Maidenhead, Eton and Windsor. However Datchet suffered on a greater scale so will need flood protection.

47
Q

Banbury flood management reasons why

A
  • 1998 - cost £12.5m , 150 homes and businesses affected

* 2007 - even more properties affected

48
Q

Management strategies 2017 Banbury

A
  • embankment - 2.9 km long, height of 4.5m
  • Raising A361 - improves drainage
  • embankments and flood walls - built around Prodrive
  • Pumping station - pumps excess water into channel
  • biodiversity- New habitats (ponds, hedgerows, trees) to absorb and store excess water. Reservoir (100,000 tons of earth was extracted)
49
Q

Economic evidence for evaluation of success Banbury

A
  • costs £18.5m

- protects 441 homes and 73 businesses worth £100m

50
Q

Social evidence for evaluation of success in Banbury

A
  • Raising A361 ensures access routes during flooding

- Quality of life improved e.g. Footpaths

51
Q

Environmental evidence for evaluation of success in Banbury

A
  • new reservoir and habitats

- biodiversity action plan has created new ponds, trees and hedgerows

52
Q

Explanation of how river processes changed for Banbury

A

Encouraging flooding north of Banbury and recovering flow of river through the sluice gates of the embankments reduces river energy and encourages deposition which leads to silting of the channel, reducing the channel capacity and causing more flooding.
Regular dredging is needed to address this.

53
Q

Factors affecting rate of erosion

A
  • energy of waves
  • size and shape
  • resistance of the coastline
  • gradient of sea floor
54
Q

Example of Mass movement

A

Rotational slip:

  • impermeable under permeable rock
  • water saturates permeable
  • slips in a rotational manner
55
Q

How are levees formed

A

When deposition raises the riverbed so the channel cannot carry as much water, so during flooding, the water flows over the side of the channel and deposits on the banks raising the height of the levees