Rivers Flashcards

1
Q

What is the source of a river?

A

The beginning of a river.

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2
Q

What is the mouth of a river?

A

The end of a river

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3
Q

What is a tributary?

A

a small river that flows into a larger river

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4
Q

What is a confluence?

A

where two rivers meet

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5
Q

What is a watershed?

A

the border between two drainage basins

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6
Q

What is an estuary?

A

the tidal section of a river near the mouth

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7
Q

What is a channel?

A

The physical confines of the river, encompassing two banks and a bed

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8
Q

What is a drainage basin?

A

an area of land that is drained by a river and its tributaries

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9
Q

What is vertical erosion?

A

High turbulence causes the rough, angular particles to be scraped along the river bed, causing intense downwards erosion.

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10
Q

What is lateral erosion?

A

This widens t he river valley during the formation of meanders.

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11
Q

What is the long profile of a river?

A

This is the longitudinal section of the river from source to mouth showing vertical changes. It is used to divide the river into upper, middle and lower course.

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12
Q

What is the base level of a river?

A

This is the lowest level to which s river can cut down.

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13
Q

What is the cross profile of a river?

A

The cross section across a river channel or valley.

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14
Q

What is the bradshaw model?

A

A geographical model that shows how a river’s characteristics change and vary between the lower and upper courses.

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15
Q

What is hydraulic action?

A

results from the sheer force of the water hitting the rover beds and banks.

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16
Q

What is abrasion?

A

caused by material carried in the river rubbing against the bed and banks of the channel

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17
Q

What is solution?

A

The river water is slightly acidic so can dissolve some rocks and minerals

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18
Q

What is attriton?

A

Sediment particles carried in the rover collide with each other breaking chunks off.

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19
Q

What is traction?

A

stones roll across the river bed

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20
Q

What is saltation?

A

Particles jump across the riverbed in a leapfrog movement

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21
Q

What is suspension?

A

silt and clay sized particles are carried within the water flow.

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22
Q

What is solution?

A

some minerals dissolve in the water

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23
Q

What is soil creep?

A

When individual particles of soil move slowly down a slope

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24
Q

What is sliding?

A

When materials move rapidly downslope in one go. Often rotates as it moves

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25
Q

What are flows?

A

Masses of soil or rock, flows like liquid downhill.

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26
Q

What is deposition?

A

When a rover no lo get his enough energy to carry its load, deposition occurs.

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27
Q

explain the impact that storms can have on river landforms

A

Storms can cause a sudden in crease in river discharge and velocity This increases the rate of erosion and sediment transport and means that landforms will be widened and deepened by increased hydraulic action and abrasion. The river can flood and sediment is deposited on the flood plain. This raises the height of the floodplain and the levées, which are parallel to the river.

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28
Q

What is a v shaped valley?

A

a valley which resembles a V shape

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29
Q

What are interlocking spurs?

A

Ridges of more resistant rocks around which a river is forced to wind.

30
Q

How are V shaped valleys and interlocking spurs formed?

A
  1. river is vertically eroded
  2. steep sides attacked by weathering
  3. loosened material creeps down the slope due to gravity.
  4. the result is a steep sided v shaped valley.
31
Q

How are waterfalls formed?

A

Due to river erosion and the geological influence of the area.

  1. a band of resistant rock lies over a band of less resistant softer rock.
  2. The less resistant rock is eroded more quickly, it is undercut and leave the more resistant rock hanging in a lip until it becomes too heavy and falls into the river below.
32
Q

What is the area at the bottom of a waterfall called?

A

a plunge pool

abrasion and hydraulic action occurs here.

33
Q

How are meanders formed?

A
  1. The flow of the water is faster on the outside of the bend.
  2. so more erosion takes place, forming river cliffs
  3. Current is slower in the inside of the bend
  4. eroded material is deposited causing a slip off slope
34
Q

How are oxbow lakes formed?

A
  1. The area between the large meander loop gets eroded.
  2. `river floods so water cuts straight across meanders neck.
  3. This process is repeated until eventually deposition infills and detaches the loop.
35
Q

How are levées formed?

A
  1. in times of flood, water and sediment come out of the channel
  2. as it overflows the river loses energy - depositing some the larger and heavier sediment on the banks
  3. this process repeats until the banks get higher, forming levées.
36
Q

What is a flood plain?

A

The flat area of land either side of a rover in its Lowe course.

37
Q

How are flood plains formed?

A

By erosion and deposition

38
Q

What is the valley cross section and features at the upper courses a river?

A

V-shapes
interlocking spurs
steep gradient

39
Q

What is the valley cross section and features in the middle course of a river?

A

open v-shape
flatter valley floor
sloping valley sides

40
Q

What is the valley cross section and features in the lower course of a river?

A

wide and flat
flood plain emerges
levées
meander scars

41
Q

What processes are at work in the upper course of the river?

A

vertical erosion, cutting downwards

42
Q

What processes are at work in the middle course of the river?

A

some vertical erosion

more lateral erosion which widens the valley

43
Q

What processes are at work in the lower course of the river?

A

lateral erosion on outside bends of meanders
limited vertical erosion
deposition increases

44
Q

What are the main features in the upper course of a river?

A

pools
potholes
river narrow and turbulent
rapids and waterfalls

45
Q

What are the main features in the middle course of a river?

A

meanders
river cliffs
slip off slopes
river channel is broader and flatter

46
Q

What are the main features in the lower course of a river?

A

ox bow lakes
levées
mud flats
salt marshes

47
Q

What are the human land uses at the upper course of a river?

A

sheep farming
dams
tourism
coniferous plantations

48
Q

What are the human land uses at the middle course of a river?

A

land is cultivated for crops and animals

market towns and villages

49
Q

What are the human land uses at the lower course of a river?

A
intensive farming 
towns 
cities 
ports 
land becomes increasingly urban as the sea is approached.
50
Q

What is river discharge?

A

The volume of water that flows in a river per second.

51
Q

What is river discharge measured in?

A

cumecs - cubic metres per second.

52
Q

What do hydrographs and storm hydrographs show?

A

hydrographs show how the discharge at a certain point in a river changes over time.
storm hydrographs show the changes in river discharge around the time of a storm.

53
Q

What is peak discharge?

A

The highest discharge in the period of time you’re looking at

54
Q

What is lag time?

A

The delay between peak rainfall and peak discharge

55
Q

What is rising limb?

A

The increase in river discharge as rainwater flows into the river.

56
Q

What is falling limb?

A

The decrease in river discharge as the river returns to its normal level.

57
Q

how does relief affect hydrographs?

A

If the drainage basin has steep sides. Water will run off quickly and have little time to percolate into soils.

58
Q

how does rock permeability affect hydrographs?

A

If the bedrock is impermeable less water can infiltrate so there will be lots of surface water. This results in a short lag time and a higher peak discharge than in a basin with permeable rock.

59
Q

what human activities have affected river landscape?

A
  • building of settlements on river valleys, affects the visual impact and impact wildlife
  • farming, trees have been felled for land, and impact wildlife as trees are used for habitat
60
Q

When does flooding occur?

A

Flooding occurs when a river’s discharge exceeds its channel volume, causing the river to overflow.

61
Q

What physical factors cause flooding?

A
  • heavy rainfall
  • prolonged rainfall
  • sudden rise in temperature
  • geology
62
Q

what human causes affect flooding?

A
  • urbanisation
  • building on the flood plain
  • deforestation
  • global warming
63
Q

What affects can flooding have in the environment?

A
  • soil erosion
  • loss of wildlife habitats
  • landslides
64
Q

What affects can flooding have on people?

A
  • death and injury
  • damage to property
  • loss of crops and livestock
65
Q

define soft engineering

A

A method of river management which works or attempts to work with the natural processes occurring. They tend to be visually unobtrusive. It doesn’t tend to involve major construction work.

66
Q

define hard engineering

A

A method of river engineering which involves major construction work.

67
Q
What is a dam?
Give an example
What type of engineering is it?
Name some advantages and disadvantages 
Impact in the environment
A
  • a large concrete structure built across a rover valley to hold back water
  • The Derwent dam in Yorkshire
  • hard engineering
    Advantages : effective for many years, very visible which makes residents feel save
    disadvantages : very expensive to build, seen as ugly which puts tourists off
    impacts - sediment van be trapped behind the dam causing lack of deposition further downstream
  • can cause problems with salmon making their way upstream
68
Q
What is a reservoir?
Give an example
What type of engineering is it?
Name some advantages and disadvantages 
Impact on the environment
A
  • a large area of water created after the flow of a river has been controlled, often by building a dam
  • The Derwent reservoir Yorkshire
  • hard engineering
    advantages : can provide drinking water for urban areas, creates a large area of water that ca be used for recreational activities
    disadvantages : very expensive , settlements can be lost if floods
    impacts: - river landscapes are flooded with loss of land and settlements.
  • disrupts the natural processes.
69
Q
What is channelisation?
Give an example
What type of engineering is it?
Name some advantages and disadvantages 
Impact on the environment
A
  • The river channel is made wider, deeper and straighter
  • Reading Town centre
  • hard engineering
    advantages : long lasting , visible so residents feel safe
    disadvantages : expansive, water can travel faster to places downstream and cause flooding
    impacts: - river landscape is changed and looks unnatural
  • disrupts natural processes
70
Q
What is floodplain zoning?
Give an example
What type of engineering is it?
Name some advantages and disadvantages 
Impact on the environment
A
  • Land that is close to the river is seen as low value due to flood risk, the usage is often sports fields.
  • Reading Town centre
  • soft engineering
    advantages : potential habitat for birds =, very cheap as no defences built
    disadvantages : Large areas of land can’t be built on, flooding takes the land out of action regularly
    impacts : geology of the landscape changes everywomen river floods
71
Q
What is are washlands?
Give an example
What type of engineering is it?
Name some advantages and disadvantages 
Impact on the environment
A
  • The river is allowed to flood these areas, which could be farmland or recreational land close to settlements.
  • Reading Town centre
  • soft engineering
    advantages : provides habitats for wading birds , no defences need to be built so cheap
    disadvantages : flooding may occur downstream as floodwater is carried there faster, large area of land that cannot be built on.
    impacts - ecology of landscape left relatively unchanged.