The Water Cycle Flashcards
(145 cards)
1
Q
Precipitation
A
The falling of atmospheric water vapour, for example, in the form of rain, snow, hail and sleet.
2
Q
Condensation
A
The conversion of gas to droplets of water
3
Q
Evaporation
A
The conversion of liquid to vapour
4
Q
Transpiration
A
The evaporation of water through the stomata in a plant’s leaves
5
Q
Evapotranspiration
A
The combined total moisture transferred from the Earth to the atmosphere, through evaporation and transpiration
6
Q
Throughflow
A
Water moving horizontally through the soil, due to gravity
7
Q
Infiltration
A
The process by which water enters and moves through the soil
8
Q
Percolation
A
The process by which water enters and moves through the rock
9
Q
Residency time
A
The amount of time something is held in a store.
10
Q
What are the longest stores?
A
Deep oceans and ice.
11
Q
What are the shortest stores?
A
Clouds + the surface of puddles, lakes etc., because lots of evaporation occurs
12
Q
Albedo Effect
A
The refraction of the solar radiation by ice
13
Q
Is the Albedo Effect an example of positive or negative feedback?
A
Positive feedback
14
Q
Explain how the Albedo Effect is an example of positive feedback
A
- ice reflects solar radiation
- therefore, it stays cold
- so ice grows
- and there is more of an Albedo Effect
- so it continues to stay cold
This is an example of positive feedback, because an initial change is bringing about additional change in the same direction, further distorting the system and enhancing the Albedo Effect (?)
15
Q
What is the difference between positive and negative feedback?
A
With positive feedback, an initial change will bring about an additional change in the same direction, whereas, with negative feedback, an initial change will bring about an additional change in the opposite direction. Positive feedback further distorts systems, whereas, negative feedback stops or reverses processes, meaning that the system becomes more balanced again.
16
Q
Give some negative feedback examples
A
- dam
- mass movement
- deforestation, e.g., it prevents things like throughfall
- wildfires, e.g., it stops the trees in the Water Cycle from being able to do the transfers
17
Q
How much of the Earth is covered in water?
A
3/4
18
Q
How long have the oceans been here for?
A
Almost 4 billion years (our planet was born about 4.5 billion years ago)
19
Q
What percentage of Earth’s water is in the ocean?
A
97%
20
Q
What percentage of the Earth’s water is freshwater?
A
3%
21
Q
How much of the Earth’s freshwater is accessible?
A
3% of the Earth’s water is freshwater. Within this, about 2% is locked in glaciers, ice caps and groundwater. There is only about 1% of water on Earth that is accessible and usable by humans.
22
Q
System
A
A set of interrelated components working together towards some kind of process.
23
Q
Elements
A
Things making up a system
24
Q
Attributes
A
Characteristics of the elements
25
Relationships
How the elements and their attributes work together to carry out a process.
26
Isolated systems
No input or output of energy or matter
27
Closed systems
These have inputs and outputs of energy, but not matter.
28
Open systems
These have inputs and outputs of energy and matter
29
Dynamic Equilibrium
The inputs and outputs are balanced
30
What are the Earth's 4 major subsystems?
- atmosphere
- lithosphere
- hydrosphere
- biosphere
31
Give an example of positive feedback, with regards to CO2 levels in the atmosphere
- global temperature rise
- leads to increased oceanic temperatures
- which leads to dissolved CO2 released by warmer oceans
- resulting in more CO2 in the atmosphere
- leading to a global temperature rise
32
Give an example of negative feedback, with regards to CO2 levels in the atmosphere
- increased use of fossil fuels
- leads to an increase in atmospheric CO2
- so there is more plant growth
- which reduces atmospheric CO2
- we continue to use fossil fuels more
33
How big is the Antarctic ice sheet?
The Antarctic ice sheet extends almost 14 million km squared
34
Effect of rising temperatures on permafrost
As climate warms, the permafrost has begun to melt. This melting releases large amounts of carbon dioxide and methane.
35
Approximately what percentage of the planet's surface do oceans cover?
Approximately 72%
36
What is the main ecosystem in the Arctic?
Wetlands
37
Why do polar areas tend to be quite dry?
Because cold air can't hold as much water as warm air
38
Sublimation
The change in state from solid to gas
39
Deposition
The change in state from gas to solid
40
Evaporation
The change in state from liquid to gas
41
Ice melt
Ablation
42
Ice gain
Accumulation
43
When do interglacial periods occur?
When ice melt (ablation) exceeds ice gain (accumulation)
44
Accumulation
Ice build up year on year
45
How long does it take for the weight of the snow to squeeze out all the air, forming ice?
About 20 years
46
Ice is a ......
Preserver
47
How often does ablation happen?
Seasonally
48
After around how many years does the Earth change from being in a glacial period to being in an interglacial period?
Roughly every 100,000 years
49
What are the 3 main reasons for natural climate change?
- sunspots
- volcanic eruptions
- The Milankovitch Cycles
50
The more sunspots you have ......
The hotter the sun
51
What can volcanic eruptions do to global temperature?
They can cool it down
52
The Milankovitch Cycles
When we move from being on a more circular orbit to a more elliptical orbit - we will have periods closer to the sun and periods further from the sun. This happens about every 100,000 years
53
What do The Milankovitch Cycles coincide with?
The glacial and interglacial periods
54
Convectional rainfall
When the sun heats the earth's surface and causes water to evaporate, changing it to water vapour. When air is hot, it rises, cools and condenses to form rain.
55
Frontal rainfall
Occurs when a warm front meets a cold front. The moisture in the warm air condenses as it cools, which causes clouds and rain.
56
Relief rainfall
Occurs when warm moist air from the Atlantic Ocean rises up over mountains
57
Jet streams
A ribbon of very strong winds. The stronger the temperature gradient, the stronger the jet.
58
What are the 3 main types of rainfall?
- relief
- frontal
- convectional
59
Water balance
Shows the state of equilibrium in the drainage basin between the inputs and the outputs
60
What does the water balance affect?
How much water is stored in a system
61
Positive water balance
Where there is a surplus of water. In the UK, this tends to occur in winter.
62
Negative water balance
Where there is a deficit of water. This can be for part of the year or for the whole year and can lead to droughts. In the UK, this tends to occur in the summer.
63
Give two things which require a positive water balance
Power plants and factories need a big supply of water
64
What does a negative water balance mean we have to do?
We need to do things to manage our water supply, for example by having hose pipe bans.
65
What happens when precipitation is greater than evapotranspiration?
A positive water balance (a water surplus) is created
66
What happens when evapotranspiration is greater than precipitation?
A negative water balance (a water deficit) is created
67
Why is soil moisture important?
Because it affects the upward and downward movement of water
68
What does field capacity refer to?
The condition of the soil in relation to soil water. If a soil has been saturated, once infiltration has ceased and the gravitational water has drained away, the soil is said to be holding its field capacity.
69
Input to the water balance
Precipitation
70
Output to the water balance
Evapotranspiration
71
If you have lots of rain, what will happen to the runoff?
Runoff will be rapid, because it's so quick that it can't infiltrate that fast
72
What will happen to the runoff if precipitation falls as snow?
You will have little runoff, as it will just sit there
73
Do you get more or less runoff when you have a heatwave and why?
You get much higher runoff when you have a heatwave and the ground is baked. This is because it can't infiltrate.
74
What effect does urbanisation have on runoff?
Urbanisation will increase runoff, because there are more impermeable surfaces, such as concrete, meaning the water cannot infiltrate and therefore, runoff will increase.
75
How much of the Northern Hemisphere does permafrost cover?
Around 1/4
76
How much does sea level rise increase per year?
Around 3.6 mm
77
What causes floods?
- high precipitation
- sea level rise
- impermeable rock
- location (e.g., if situated in a valley)
- storm events
- heavy rainfall
- deforestation, change in land use
78
How does a flood happen?
When the water can't flow away quickly enough when the banks overflow. It can result in water spilling out onto floodplains, which is an issue because we build on floodplains
79
Peak precipitation
The highest level of rainfall you had in this period of time
80
Lag time
Length of time between getting highest amount of rainfall to highest amount of flow.
81
How is precipitation always measured on a flood hydrograph?
In bars
82
Rising limb
The rising level of water in the river
83
Cumecs
Cubic metres a second
84
Peak flow / discharge
The highest level the river reaches
85
Bankfull discharge
The maximum amount of water the river channel has the capacity to hold. Anything above this = flood.
86
Falling limb / recession
Height of river level is receding
87
Storm flow
All of the excess storm water in your river
88
Baseflow / Groundwater flow
Normal river height, the normal amount of water in the river
89
Drainage basin
An area of land drowned by a river and its tributaries
90
What are drainage basins a component of?
The hydrological cycle and are local open systems
91
Watershed
An area or ridge of land that separates waters flowing to different rivers, basins, or seas. Usually, this is a ridge of high land
92
Give a tributary of the River Thames
The River Lea
93
What is knowledge of drainage basins needed for?
Preventing flooding, ensuring a secure water supply and for building properties.
94
Is a drainage basin an open or closed system?
Open
95
Inputs to a drainage basin
Rain (precipitation)
96
Outputs to a drainage basin
Loss of water / sediment, evaporation
97
Water table
The level below which the ground is saturated with water.
98
Where is there water stress in the UK?
In the south-east
99
Trees which lose their leaves
Deciduous
100
Trees which don't lose their leaves
Coniferous
101
Do deciduous or coniferous trees have a greater stem flow and why?
Deciduous have a higher stem flow, because they have a bigger tree trunk and more branches
102
Physical factors affecting drainage basins
- vegetation cover
- relief of the land
- climate
- soil type
- rock type
103
Human factors affecting drainage basins
- reservoirs
- over-abstraction
- deforestation
- urbanisation
104
Physical factor affecting drainage basins: vegetation cover
When an area has a high coverage of vegetation, the interception and evapotranspiration increases, but the surface runoff decreases
105
Physical factor affecting drainage basins: relief of the land
Steeper slopes mean faster surface runoff and shorter times for water storage
106
Physical factor affecting drainage basins: climate
Where cold climates allow for precipitation to fall as snow, the water can be stored and held until it is thawed (melted). This may reduce the channel flow during the winter, but lead to an increase during the spring and summer months, due to glacial melt water.
107
Physical factor affecting drainage basins: soil type
Impermeable soils can stop infiltration and lead to surface saturation, resulting in increased runoff. Where there are permeable soils, infiltration and percolation can happen. This can cause groundwater to recharge.
108
Physical factor affecting drainage basins: rock type
Some rocks are impermeable and can stop the infiltration of water into the ground. Similarly to impermeable soils, these types of rocks can cause the ground to saturate and lead to surface runoff, increasing flows in rivers - in contrast, permeable rocks allow for infiltration and percolation to happen
109
Human factor affecting drainage basins: reservoirs
Reservoirs are man-made stores that disrupt the natural water flow, by delaying the flow and increasing water lost from evaporation. Dams reduce the water flow further downstream, resulting in loss of vegetation. When vegetation grows on the reservoir's surface, and increase in evapotranspiration happens and in turn, increase in salinity of the water.
110
Human factor affecting drainage basins: over-abstraction
Abstraction is the process by which humans remove water from underground water stores (e.g., aquifers). Over-abstraction is when the volume of water being removed is greater than the volume of groundwater being replenished. Over-abstraction can lead to rivers drying up during periods of low rainfall.
111
Human factor affecting drainage basins: deforestation
Deforestation is the term used to describe the removal of trees. The impact of deforestation reduces interception and consequently, rainfall strikes soil directly, leading to soil compaction. Soil compaction and the removal of tree roots can reduce infiltration. Ultimately, deforestation causes an increase in surface runoff, resulting in more soil erosion and flooding.
112
Human factor affecting drainage basins: urbanisation
Urbanisation is a change of land use that results in moving away from the natural environment to towns and cities. Urbanisation leads to a large number of impermeable surfaces (i.e., tarmac, slate, concrete). These impermeable surfaces reduce infiltration, whilst increasing surface runoff.
113
Give an example of a drainage basin
The Ganges drainage basin
114
The Ganges drainage basin
A river system that has its source in the eastern Himalayas and covers an area of 1.758 million km squared. It is the most densely populated river basin in the world with over 500 million people living within it.
115
Where does much of the source water for the Ganges river basin come from?
Much of the source water is produced from ice and snow melt rather than precipitation
116
Give some characteristics of a drainage basin
- watershed
- source
- mouth
- tributary
- confluence
117
Source
The start of a river within the basin
118
Mouth
Where the river meets the sea
119
Tributary
A smaller stream which feeds into the main river
120
Confluence
The point at which two rivers meet
121
What 3 ways can water be lost from the drainage basin system?
- runoff
- evaporation
- transpiration
122
Stores within a drainage basin system
- lake storage
- interception by vegetation
- absorption by vegetation
- groundwater
- soil storage
- channel storage
123
Transfers within a drainage basin system
- surface runoff
- infiltration
- percolation
- throughflow
- groundwater flow
- stemflow
124
Water balance
The balance between the inputs and outputs of a drainage basin
125
Recharge
After a period of water deficiency, precipitation will occur and replace the lost water in the soil. This needs to occur before a period of surplus can reoccur.
126
Field capacity
The maximum amount of water that soil can hold before it becomes saturated
127
What do flood hydrographs show?
These are graphs that show how a drainage basin responds to a period of rainfall. They are used to plan for flood situations and times of drought. They show the river discharge that occurs as a result of precipitation from an earlier storm.
128
Natural changes and impacts upon runoff
- seasonally, the amount of precipitation will change. For example, in the UK, there is an increased amount of precipitation during the winter months compared to the drier summer months
- weather events, such as storms and drought conditions, can also impact upon the amount of runoff within the basin and the flow shape on the hydrograph. During storms, high levels of precipitation can lead to soil water storage limits being reached and the soil becoming saturated. This leads to increased surface runoff, which increases the discharge within the river channel.
- over time, drought conditions can harden and bake the soil = ground becomes impermeable. Therefore, subsequent rainfall following a period of sustained drought can then lead to rapid runoff and flooding.
129
Human changes and impacts upon runoff
- increased urbanisation, agricultural land use and over-abstraction
130
Drainage divide
The boundary between drainage basins
131
What are drainage basins separated by?
Watersheds
132
How many major drainage basins are in the north-east of England?
3
133
What are the 3 major drainage basins in the north-east of England?
The Tyne, Tees and Wear
134
Physical factors affecting runoff
- time of year
- storm conditions
- vegetation cover
- soil saturation levels
- topography and relief
135
Human factors affecting runoff
- agricultural land use
| - urban land use
136
What factors affect flood hydrograph dynamics?
- size
- shape
- topography + relief
- heavy storms
- lengthy rainfall
- snowfall
- vegetation
- rock type
137
What is discharge measured in?
Cumecs
138
Discharge
The volume of water flowing through a cross-section of the river during a given period.
139
What is the time between the end of rainfall and peak of discharge known as?
Lag time
140
Give 3 ways in which the rainwater may reach the river channel
- overland flow
- throughflow
- baseflow
141
Antecedent discharge
The level of discharge before the storm
142
When is there small antecedent discharge and why?
In summer, antecedent discharge is small, because there has been little precipitation.
143
When is there higher antecedent discharge and why?
In winter, antecedent discharge is much higher, because there has been heavy and continuous precipitation
144
Water budget
A measure of the amount of water entering and the amount of water leaving a system. It is the annual balance between precipitation, evapotranspiration and runoff.
145
What does the soil moisture budget show?
The levels of water in the soil
