Water on the Land Flashcards

1
Q

What is the definition of erosion?

A

The wearing away of rock and soil along the river banks and beds or breaking down of rock particles carried by the river

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2
Q

What is transportation?

A

the movement of eroded material downstream. (From point of erosion to point of deposition)

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3
Q

What is deposition?

A

When a river loses energy, it will drop/deposit some of its load (often near the mouth of the river)

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4
Q

What is hydraulic action?

A

The sheer force of the river hitting the bed and banks (causing erosion)

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5
Q

What is abrasion?

A

The load continually hits the river bed/banks, causing material to break off

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6
Q

What is corrosion?

A

Erosion which occurs when the river flows over certain types of rock (e.g. chalk or limestone)

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7
Q

What is attrition?

A

Stones/boulders, carried by the river, hit against each other and erode eachother

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8
Q

What is traction?

A

The heaviest stones in the load are rolled along the river bed by the river

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9
Q

What is saltation?

A

Stones/pebbles are bounced along the river bed, they cannot be carried for long

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10
Q

What is suspension?

A

Particles of rock are suspended in the river and transported in this way

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11
Q

What is solution?

A

Dissolved load carried by the river (not visible) only certain types of rock (e.g. chalk or limestone)

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12
Q

What is the discharge?

A

The amount of water in the river channel

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13
Q

What attributes of the river increase downstream?

A

Discharge, channel width, channel depth, speed, load quantity

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14
Q

What attributes of the river decrease downstream?

A

Load particle size, channel bed roughness, gradient of land

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15
Q

Why does channel width increase downstream?

A

There is less vertical erosion and more lateral erosion

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16
Q

Why does the channel depth increase downstream?

A

Although vertical erosion is less dominant it still continues to occur downstream

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17
Q

How does the shape of the valley change downstream?

A

The valley goes from a ‘v-shape’ to a ‘u-shape’

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18
Q

Where are waterfalls usually found?

A

In the upper course of the river

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19
Q

What is water stress?

A

Water stress is the difference between the rainfall and the demand for water (when there is an inadequate supply)

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20
Q

What is an are of deficit water supply?

A

An area with higher demand than supply of water

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21
Q

What is an area of surplus water supply?

A

An area with higher supply than demand of water

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22
Q

How has the water usage per household changed?

A

It has risen by 70% over the last 30 years

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23
Q

What is the source?

A

The beginning of the river

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24
Q

What is a confluence?

A

Where two rivers meet

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25
Q

What is a watershed?

A

An area of high land between two drainage basins

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26
Q

What is a tributary?

A

A small river or stream that flows into a larger river

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27
Q

What is a drainage basin?

A

The area drained by a river and its tributaries

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28
Q

What is precipitation?

A

Any form of water entering the basin from the atmosphere (rain/hail/snow etc)

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29
Q

What is transpiration?

A

Water released by plants during respiration

30
Q

What is surface storage?

A

Where water is stored on the Earth’s surface as lakes, rivers or surface depression storage (puddles)

31
Q

What is surface runoff/overland flow?

A

Water flowing over the surface of the ground under the influence of gravity

32
Q

What is infiltration?

A

The downward movement of water from the surface through into the soil

33
Q

What is soil water storage?

A

Where water is stored in the soil

34
Q

What is through flow?

A

Where water flows through the soil under the influence of gravity, to drain into the nearest river or lake

35
Q

What is groundwater storage?

A

Water which is stored in porous/pervious rock

36
Q

What is groundwater flow?

A

Water which flows through the rock layer parallel to the surface

37
Q

What is percolation?

A

Water flowing through the rock layer into the groundwater store

38
Q

What is the water table?

A

The line that divides the saturated rock/soil from the unsaturated rock/soil

39
Q

When did the Bangladesh floods occur?

A

July 2004

40
Q

Which three river flow through Bangladesh?

A

The Ganges, The Meghna and The Brahmaputra

41
Q

What human factors mean that Bangladesh is susceptible to floods?

A

Deforestation, irrigation for farming, global warming, built-up areas and poorly maintained embankments (on the river)

42
Q

What physical factors mean that Bangladesh is susceptible to floods?

A

70% Bangladesh under 1 m above sea level, 10% land area is lakes or rivers, heavy monsoon rains, tropical storms

43
Q

How much of the Bangladesh was flooded in 2004?

A

60% country and 40% of the capital Dhaka

44
Q

How may people were affected by the 2004 Bangladesh floods?

A

750 direct deaths, 20 million homeless and secondarily 100,000 in Dhaka suffered from diarrhoea

45
Q

How much damage was caused by the 2004 Bangladesh floods?

A

$7 billion of damage, 0.5 million livestock lost and 2 million tonnes of rice crop destroyed

46
Q

When were the Tewkesbury floods?

A

July 2007

47
Q

Which rivers flow through this area in Gloucestershire?

A

The Severn and The Old Avon

48
Q

What human factors resulted in the Tewkesbury floods?

A

Bad flood defences, new building developments built on floodplains

49
Q

What physical factors resulted in the Tewkesbury floods?

A

2 months of rain fell in 14 hours, June and July were the wettest moths on record (since 1766), jet stream was located further south than usual, Tewkesbury is on a confluence and a floodplain

50
Q

How many people were affected by the Tewkesbury floods?

A

2 people died, 350,000 people were left without water, 10,000 motorists stranded on the M5, 500 stranded at Gloucestershire train station

51
Q

What is the space between peak rainfall and peak discharge? On what graph is it shown?

A

The lag time, and it is shown on a flood hydrograph

52
Q

What is different about a flash flood on a flood hydrograph?

A

A flash flood has a higher peak rainfall and peak discharge. It also has a shorter lag time

53
Q

What is the “cap rock” on a waterfall?

A

A layer of resistant rock (an overhang) over which the river flows

54
Q

Why is an overhang created on a waterfall?

A

The rock underneath the “cap rock” is softer; so is preferentially eroded, which undercuts the harder rock (forming an overhang)

55
Q

What is found in front of a waterfall?

A

A gorge (of recession)

56
Q

How is a waterfall (and gorge of recession) formed?

A

Step, plunge pool, overhang, overhang collapse, waterfall recedes (gorge of recession), process repeats

57
Q

How is a “step” (in terms of waterfalls) created?

A

River runs over horizontal (or slightly dipping) beds of hard and soft rock. As river reaches softer rock it is preferentially eroded, creating a step.

58
Q

How are meanders formed?

A

Water has lateral energy, fast outer flow erodes, slow inner flow deposits; this forms meanders

59
Q

How is an ox-bow lake formed?

A

As a meander continues to become more extreme it eventually forms a swan’s neck. Eventually the two sides meet- cutting off a u-shaped lake; an ox-bow lake

60
Q

How are meander scars formed?

A

When a more direct river course is created- and an ox-bow lake is formed, the lake has very little water supply- so eventually dries out- leaving a meander scar

61
Q

Can you name land-form from each part of a river’s course?

A

Upper: waterfall, middle: ox-bow lake, lower: floodplain

62
Q

What is channel storage?

A

Where water is stored in the river channel

63
Q

What is channel flow?

A

Where water is carried in the river channel to a confluence or to the river mouth

64
Q

What is interception?

A

Where water is prevented from hitting the ground by trees/vegetation

65
Q

What is evaporation?

A

What is heated and transforms into water vapour

66
Q

Why were the Elan valley dams introduced?

A

To supply the working population of Birmingham with clean water (due to industrial revolutions during 19th C)

67
Q

When did building work begin for the Elan valley dams?

A

1893

68
Q

What was the average rainfall in the Elan valley?

A

During the late 1800 s, it was about 1830 mm annually

69
Q

When were the Elan valley dams opened?

A

21st July 1904

70
Q

When was the capacity of the Elan valley dams increased?

A

Claerwan dam was built doubling capacity to 345.5 million litres a day between 1948 and 1952