Water On The Land Flashcards
1
Q
What is headwaters
A
The beginning or source of a river
2
Q
What is a river flow
A
The amount of water in the channel
3
Q
What is a river channel
A
The path a river takes is called a channel it’s shape and size depends on the amount of water that has been flowing in it, how long it’s been flowing and the type of rocks and soil over which it flows
4
Q
What is a floodplain
A
A flag low lying area along the river that gets covered with water when the river overflows
5
Q
What is a river bank
A
The land immediately along the river
6
Q
What is wetlands
A
A low lying area where wafer covers the soil for much of the year
7
Q
What is a river mouth/ delta
A
The end of the river where it meets a lake or ocean
8
Q
What is a river
A
A moving body of water which flows downhill from the place it begins, the source, to the point it enters the sea or lake,the mouth.
9
Q
What is the point called when a tributary joins the main river
A
Confluence
10
Q
What is the area of land which is drained by the river and its tributaries called
A
Drainage basin
11
Q
What is the boundary of the drainage basin called and its characteristic
A
The watershed and is usually a ridge of high land
12
Q
Why does the landscape change as it gets further down the river
A
A result of the processes of erosion, transportation and deposition. The extent it can change is a result of how much energy the river has and how resistant the land is
13
Q
What is the hydrological cycle
A
The cycling of water through the sea land and atmosphere
14
Q
What is precipitation
A
Water in any form which falls to the earth it includes rain sleet snow and hail
15
Q
What is interception
A
Where vegetation catches precipitation
16
Q
What is surface runoff
A
Water flowing over the land towards the channel as a result of very heavy rain or the soil being saturated
17
Q
What is infiltration
A
The downward movement of water from the surface into the soil pores
18
Q
What is throughflow
A
The movement of water sideways through the soil towards the river
19
Q
What is groundwater
A
Water stored mainly within the pores of underlying rocks such as sandstone
20
Q
What is groundwater flow
A
Water moves slowly through the bedrock towards the river. This flow can keep rivers flowing for many months without rain
21
Q
What is a water table
A
The level below which the ground is saturated
22
Q
What is evaporation
A
The process by which liquid water changes to water vapour when warmed
23
Q
What is transpiration
A
The process by which plants give off water vapour via the pores in their leaves w
24
Q
What is condensation
A
The process by which water vapour changes to liquid water when cooled
25
What is erosion
The wearing away of the river channel by water and its load (=material carried in river)
26
What is abrasion.
The river carries particles of sand and moves pebbles at times of high flow. This material rubs against the bed and banks of the river and wears them away
27
What is attrition
The load being carried by the river collides and rubs against itself breaking up into smaller pieces and become smoother
28
What is solution
Some rock minerals such as calcium carbonate dissolve in river water which is sometimes acidic
29
What is hydraulic action
The force of the water on the bed and banks of the river it is particularly powerful in times of flood. Once material is eroded it will be transported
30
What is traction
Large boulders roll along the river bed needing a lot of energy
31
What is saltation
Smaller pebbles are bounced along the river bed picked up and then Dropped as the flow of the river changes
32
What is suspension
The finer sand and silt sized particles are carried along in the flow giving the river a brown appearance
33
What is solution
Minerals such as limestone and chalk dissolve in the water and carried along in the flow and can't be seen
34
What doesn't the amount of load in a river depend on
```
The volume of water (can carry more)
The velocity (move larger particles)
Local rock types (some are easier to erode)
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35
Why does a river deposit sediment
When it's volume or speed decreases I.e its energy decreases
36
What is the fertile material deposited by a river called
Alluvium
37
What are four factors that encourage deposition
- a river carries a lot of sediment = more deposition
- a reduction in velocity on the inside of a meander
- an obstruction e.g a bridge in the way
- a fall in volume of a river e.g times of low flow or drought
38
What are the three stages of a rivers journey
Upper, middle and lower
39
Characteristics of the upper course of the river
- steep v-shaped valley
- narrow/ shallow channel
- high bed load
40
Characteristics of the middle course of the valley
- open/ gentle sloping valley with floodplain
- wider/ deeper channel
- more suspended sediment
41
Characteristics of the lower course of a river
- open/ gentle sloping valley with floodplain
- flat and wide flood plain
- wide open valley
- very wide and deep channel
42
Features of the upper course of the valley
V shaped valleys
Interlocking spurs
Waterfall
Gorges
43
Features of the middle course
Meanders
River cliffs
Slip off slopes
44
Features of the lower course of the valley
Ox bow lake
Flood plains
Levees
45
How do Vshaped valleys form
As the river contains a lot of potential energy the river erodes vertically down and as it erodes straight down it leaves very steep valley sides that are attacked by weathering processes like freeze thaw which weakens a valleys side so they collapse of move down due to mass movement like slumping. The river erodes this material and moves it away leaving behind the V shape.
46
What are interlocking Spurs and what do they contain
They are slithers of land that interlock as they are areas of more resistant rock left behind as the river erodes soft rock quicker so the river moves between the interlocking Spurs
47
What is the upper course of the river suitable for land use
Hill sheep farming and forestry
48
What is discharge
The volume or flow of water passing a river measuring station at a particular time
49
Why is the middle course like that
It's become less steep so there is less vertical erosion but a lot of material from the upper part of the river is being transported down and any surplus energy is used to erode sideways in lateral erosion so the valley is wider and flatter
50
What land use is suitable for the middle course of the river
It is less steep and has a wider valley and less harsh climate so suitable for villages and farming for dairy and arable farming
51
Why is the lower course of the river like that
As it gets nearer the sea the valley disappears and it has wide flood plains as the river erodes laterally
52
What is the land use for the lower course of the river
Large towns and cities
53
How is a waterfall, plunge pool and gauge formed
When resistant rock is ontop of none resistant rock erosion processes like hydraulic action and abrasion undercut the hard rock and erode the soft rock more quickly. The hard rock overhangs until it can longer be supported and it collapses creating a waterfall of water flowing over the edge and it erodes the base of the river it is hitting to create a plunge pool. This process continues to creating a gauge as the water fall retreats.
54
What are meanders and where do they occur
Bends in the rivers course and in the middle and lower valley and erode laterally and migrate across the valley floor over time widening the valley
55
Characteristics of a meander
Fastest current is found in the outside of a bend because the water is deeper so less friction and higher velocity. Force of the water erodes and undercuts outside creating a a river cliff. On the inside bend the current is slower creating deposition and sand is deposited to create a slip off slope
56
How do ox bow lakes form
Erosion on the outside bend of the meander means the neck of the meander becomes narrower. On the inside the slow flow encouraged the deposition to create slip off slopes. Eventually the neck is broken through creating a straight channel usually during a flood. This cuts off the meander bend as the flood water falls and alluvium is depositions which deals off the old meander and forms an ox-bow lake.
57
What happens when an oxbow lake dries up
It leaves a meander scar
58
What are levees
Natural embankments of silt along the banks of a river often several metres higher than the flood plain
59
How is a levee formed
Along rivers that flow slowly and carry a large load and periodically flood. When a river floods the velocity of the River on the surrounding land is slowed this is because as the surface area the water is in contact with is massively increased which increases friction and decreases energy. The coarser and heavier material will be deposited in the edge of the channel where the loss of floe due to increased friction is more only smaller material is carried further. This continues with many floods.
60
What is an estuary
The river mouth
61
What affects discharge of a river
```
Precipitation
Previous weather conditions
Relief (height and steepness)
Temperature
Rock type (permeable or impermeable)
Land use
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62
When does a flood occur
When the discharge is so great that all the water can no longer be contained within the channel so that the river over tops its banks
63
What are physical causes of river flooding
Precipitation as it increases the discharge
The relief because if it is steep it decreases lag time as it reduced the amount of infiltration
Vegetation type because forests and woods can intercept rainfall more than grass
Soil and rock type - impermeable surfaces causes surface run off
Temperature because it can help evaporation
64
What are human causes of flooding
Urbanisation as many surfaces in towns and cities are impermeable. Do have pipes to drain water away but can cause problems in other areas
Deforestation as it reduces interception. Afforestation can have the opposite effect.
Increased population density as we build on flood plains
65
What are usually used to show the discharge of a river increasing
Hydrographs
66
What are the different parts of a hydrograph
Peak precipitation, Rising limb (how fast water is reaching the river. Steeper = more likely flood) falling limb (as its levels fall) peak discharge (the highest amount of discharge in the river), lag time (which is the amount of time between the peak amount of rainfall and the peak discharge)
67
What do we use rivers for
Collecting drinking water, industry and farming, manage them to prevent damage caused by deposition erosion and flooding.
68
What is hard engineering
Using strong construction methods to hold floodwater back or keep it out it involves the building of entirely artificial structures using various materials like rock , concrete and steel to reduce or stop the rivers processes
69
What is soft engineering
Uses more natural ways to reduce the impact of flooding on humans with less intervention and more preparation, involves mimicking natural processes to protect more vulnerable areas and is more sustainable
70
What are some hard engineering strategies
Dams, straightening and deepening rivers and building flood walls
71
How do dams work
They are huge concrete and steel structures that block rivers and cussed the water carried by rivers back up and flood the valley upstream of the dam. This lets people control the flow of the water to prevent flooding.
72
How does straightening river channels work
Digging a straighter shorter channel in areas where rivers meander this speeds up water flow in flood prone areas to stop it hanging around but can cause flooding downstream
73
How does deepening river channels work
By dredging as it deepens the river so they can hold more water in its banks but can have knock on effects down stream
74
What do flood walls or embankments do
Raising the bank of the river so that it can hold more water reducing the risk of flooding
75
What are downsides to hard engineering and good sides
They are expensive to build, require costly maintanence and have bad effects for the environment but offer the most protection
76
What are three ways of soft engineering
Floodplain zoning
Afforestation
Flood warming system
Encourage growth of reed beds
77
How does flood zoning work
Areas closest to river are used for low cost things such as grazing, higher cost land used are kept away from the river on higher land but many homes and businesses have already been built on flood plains
78
How does afforestation work
Trees are planted near the river to increase interception of rainwater and lower discharge and is low cost
79
How does a flood warning system work
In the event of a flood the envionment agency will contact homeowners at risk via text or phone or visit from flood warden so they can evacuate
80
How does growing reed beds help
They are allowed to floor and slow down river water
81
What is an LEDC case study for flooding
Bangladesh
82
What are the background facts of Bangladesh
It is low lying - half of it is on a floodplain
Has 3 major rivers flowing through e.g Ganges
Dhaka had the worst rainfall in 50 years - 350mm fell in 24 hours
83
What were the effects of the Bangladesh flood
Flood covered 50% of the country
600 deaths
30 million homeless
100,000 suffered from diarrhoea from flood waters
Bridges destroyed and death toll rose to 750
Airports and roads flooded
Damage to schools and hospitals at $7 billion
Rural areas suffered, the rice crop devastated as were important cash crops like sugar
84
What were the immediate aid and response to the Bangladesh flood
Food p, medicine, clothing and blankets write distributed
Rebuilding homes
Diseases from contaminated water still a threat
Water aid brough water purification tablets and educational campaigns
85
What were the long term effects of the Bangladesh flood
Flood action plan in Bangladesh but embarkments supposed to protect haven't been successful
Flood warnings and provision of food and shelter have better impact
86
What is the case study for an MEDC food
Morpeth
87
Background facts to Morpeth
The flood walls were not high enough and the flood water simply flowed over the top of the defences
88
Human cause of the flooding in Morpeth
A lot of their houses are built on the flood plain as many date back to the 14 the century.
Building on these areas can damage a rivers natural drainage ground and push flooding further downstream
Of 1062 properties on 62 escaped destruction
89
What are the natural causing of the flood in Morpeth
Soil already saturated from the wry summer do the effect of surface run off was enhanced
Increased urbanisation meant most water drained directly into the channel
Prolonged rainfall
90
Effects of the Morpeth flood
Many residents forced from homes and lived in caravans or with relatives as rebuilding happened
Estimated damage over £10 million
Farming loses of £1 million
91
Short term response of the Morpeth flood
400 evacuated
Shelter provided in the town hall and King Edward VI high school
Fire fighters, ambulance crews, the British Red Cross emergency services involved in rescue and recovery
92
Long term responses and future management of the Morpeth flood
Environment agency is proposing creation of an upstream reservoir to restrict water volume in towns which would hold one million cubic metres
More flood walls built
93
Where is the UK water supply obtained from
Mountain lakes, upland reservoirs,river intake, underground stores in layers of porous rocks
94
What is water stress
When amount of water available doesn't meet what is required from inadequate supply or quality
95
What is areas of water deficit
Locations where the rain that falls does not provide enough water on a permanent basis shortage may occur
96
What is areas of water surplus
Areas that have more water than needed often with a small population but a lot of rainfall
97
What is conservation
Ensuring that the provision of water is long term and supplies can be maintained without harming the environment
98
What is sustainable use of water
The thoughtful use of resources managing the landscape in order to protect existing ecosystems and cultural feature
99
What is a case study for water transfer
Kielder water
100
What are some background facts to kielder water
Over 10km long
Located near Scottish boarder
Largest artificial lake in the uk
101
What were the positives of the kielder water scheme
- HEP using water from it can generate 6MW of power
- includes 8 sites of special scientific interest and contains unique plants and animals (red squirrels)
- lake is 11km long and stores nearly 200,000 million litres of water that helps in times of shortage
- timber from the 150 million trees (replanted)
- employs 260
- flood prevention
- £6 million earned through tourism each year
102
What are the negatives of Kielder water
- changes landscape of river effecting plants and animals
- dam holds back sediment
- clean water increases potential erosion down stream (clear water erosion)
- 58 families displaced
- flooded area of scenic natural beauty
- 2700 acres of farmland and habitat lost
- forest of kielder is monoculture (one type of tree)
103
What is a tributary
A river or stream that feeds into another river
