The water cycle and water insecurity Flashcards
(228 cards)
1
Q
Aquifer?
A
A permeable or porous rock which stores water
2
Q
Channel flow?
A
The water flowing in a rivulet, stream or river contained within the banks
3
Q
Closed system?
A
A sequence of linked processes with a transfer of energy but not matter between parts of the system
4
Q
Cryosphere?
A
Describes the set of all locations on earth where water is found in solid form, including areas of snow, sea ice, glaciers, permafrost, ice sheets and icebergs
5
Q
Deficit?
A
Where a resource is less than the necessary amount
6
Q
Drainage basin?
A
The area of land drained by a river and it’s tributaries. Drainage basins are separated by a ridge of high land called the watershed
7
Q
Economic water scarcity?
A
Occurs when water resources are available but there is insufficient capital to access the water to meet demand
8
Q
Evapotranspiration?
A
Combined loss of water to the atmosphere via the processes of evaporation and transpiration
9
Q
Flux?
A
The flow or flowing of a liquid
10
Q
Fossil water?
A
Water that has been contained and undisturbed for millennial. There is no significant recharge therefore it is a non-renewable resource.
11
Q
Global water budget?
A
The amount of water transferred and stored in the earths hydrological cycle each year.
12
Q
Hard engineering?
A
Often hi-tech and high-cost engineering schemes such as dams or Thames barrier
13
Q
Hydrological drought?
A
Occurs when there is insufficient soil moisture to meet the needs of vegetation at a particular time
14
Q
Infiltration?
A
The movement of water vertically downwards via spaces (pores) in the soil.
15
Q
Interception?
A
The process by which raindrops are prevented from called onto the ground via leaves, branches, twigs of vegetation.
16
Q
Monsoon?
A
A seasonal prevailing wind which causes wet and dry seasons in many sub-tropical areas
17
Q
Open system?
A
A sequence of linked processes with inputs and outputs, including transfers of energy and matter to and from other systems.
18
Q
Orographic?
A
Relating to mountains, orographic uplift if when the uplift of an air mass, because of orographic obstruction, causes the cooling of air mass. If enough cooling takes place, condensation can occur and form into orographic precipitation.
19
Q
Percolation?
A
A process similar to infiltration but travelling through rock surfaces towards the water table.
20
Q
Permafrost?
A
Zone of permanently frozen water found in high latitude soils and sediments
21
Q
Permeability?
A
The ability of a substance to allow another to pass through it, especially porous rock, sediment or soil to transmit fluid through pores and cracks
22
Q
Physical water scarcity?
A
Occurs when there’s physical lack of available freshwater resources to meet demand due to over-abstraction by agriculture, industry and domestic activity
23
Q
Porosity?
A
A surface that allows water to pass through it, such as sand
24
Q
Precipitation?
A
Any form of water falling from the sky
25
Relief?
The range of topographic elevation within a specific area
26
Resilience?
Ability to recover/adjust easily to an event or change
27
River regime?
The pattern of river discharge over a year; usually there are seasonal variations
28
Runoff?
Water (from rain, snowmelt etc) that flows over the land surface; can be due to soil saturation
29
Saltwater encroachment?
Where saline water beings to find it’s way into fresh water aquifers, especially near coastal aquifers which run low, allowing salt water to see back in and cause contamination
30
Saturated overland flow?
Occurs when the soil becomes saturated, and any additional precipitation causes runoff
31
Storm hydrograph?
Shows changes in a rivers’ discharge at a given point on a river over a short period of time (usually before, during and after a storm)
32
Water budget?
The annual balance between inputs (precipitation) and outputs (evapotranspiration and channel flow) at a place
33
Water security?
The capacity of a population to safeguard sustainable access to adequate quantity’s of acceptable quality water.
34
Water stress?
When demand for water exceeds the available amount during a certain period. Renewable water resources are between 1000 and 1700m
35
What is a closed system?
A system that does not allow a transfer of matter in or out of the system
36
Inputs of hydrological cycle?
Ocean precipitation
| Land precipitation
37
Stores of hydrological cycle?
```
Ice
Ocean
Soil moisture
Groundwater
Rivers, lakes
Land
Vegetation
```
38
Flows/processes of hydrological cycle?
Ocean to land water vapour transport
Surface flow
Ground water flow
39
Outputs of hydrological cycle?
Ocean evaporation
| Evaporation, transpiration
40
What type of system is the hydrological cycle?
A renewable one: no new water can enter the system and no new water can be lost
41
What is the water circulation in the hydrological driven by?
Solar energy- suns heat causes evaporation and transpiration
Gravitational potential energy- water accelerates under gravity causing it to flow
42
Why is fossil water considered non-renewable?
Will require significant amount of energy to obtain
Taken out of the store and not replaced
43
Of the fresh water present, where is most of it?
Locked up or bellow surface as ground water
44
Where is 68% of water found?
In icecaps or glaciers
45
Where is 30% of water found?
Groundwater
46
What does ITCZ stand for?
Inter tropical convergence zone
47
What type of pressure can be found at the equator?
Low pressure
48
What type of pressure can be found at the tropics?
High pressure
49
What type of pressure can be found at the polar regions?
High pressure
50
How many cells of circulating air are there?
Six
51
Why is the sun most intense at the equator?
Suns rays are most concentrated here
52
What does intense solar radiation result in?
Rising air
53
What type of rainfall can be found at the equator?
Convectional rainfall
54
What type of system is the drainage basin?
An open system within the closed global hydrological cycle
55
What is the definition of a drainage basin?
An area of land drained by a river and its tributaries with a boundary, usually composing of hills and mountains
56
What are the 5 main stores in the drainage basin?
```
Channel storage
Groundwater storage
Surface storage
Soil moisture storage
Interception storage
```
57
What is the main input in the drainage basin?
Precipitation
58
What are the 7 main flows in the drainage basin?
```
Throughfall
Stemflow
Surface runnoff
Infiltration
Groundwater flow
Percolation
Channel flow
```
59
What are the 3 physical factors that affect the drainage basin INPUTS?
Seasonality
Variability (long term changes to climate)
Latitude
60
What is interception?
Process by which raindrops are prevented from falling directly onto ground surface by a layer of vegetation
61
What is Infiltration?
The movement of water vertically downwards through pores in soil
62
What is Surface runoff?
Water flows overland, rather than permeating deeper levels of the ground.
63
What is Throughflow?
A down slope movement under the influence of gravity towards a stream or river through the soil
64
What is Percolation?
Water moves from the ground or soil into porous rock or rock fractures. The rate is dependent on the fractures that may be present + the permeability of the rock
65
What is groundwater flow?
The gravitational transfer of water through porous rock, under the influence of gravity. Water can sometimes become trapped within these deep layers of bedrock, resulting in aquifers.
66
What is infiltration capacity?
Is the maximum rate at which the soil can absorb precipitation
67
What is soil capacity affected by?
Soil composition
Previous precipitation
Type and amount of vegetation
Relief of land
68
What is the primary transfer of water to river channels?
Surface runoff
69
What are the 6 physical factors affecting drainage basin FLOWS?
```
Interception
Infiltration
Surface run off
Through flow
Percolation
Groundwater flow
```
70
What are the two physical factors affecting drainage basin OUTPUTS?
Evaporation
| Transpiration
71
What is transpiration?
A biological process where water is lost to atmosphere via pores of plants (stomata).
72
What is transpiration affected by?
Seasonality
Vegetation
Moisture content
73
What is evaporation also dependent on?
Volume and surface area of the water body
Vegetation cover
Colour of surface beneath the water
74
What are the 3 rainfall types?
Conventional
Frontal/cyclonic
Relief/orographic
75
Conventional rainfall?
Often a daily occurrence. Morning heat warms the ground in turn heats low level moisture which evaporates and rises. It cools and condenses to form rain. Very common in tropical climates.
76
Frontal/cyclonic rainfall?
Where two air masses meet, a wedge can occur of hot air within cold air (a depression). At the front, warm moist air is forced to rise above the cold air mass, causing the water moisture within it to cool and condense
77
Relief/orographic rainfall?
When warm moist air meets land of high relief, the air masses are forced to rise above the hill to continue travelling. As it rises, air masses cools and the moisture in it hun it condenses to form clouds and rainfall.
78
What are the 6 human (anthropogenic) factors that disrupt the drainage basin system?
```
Cloud seeding
Urbanisation
Change in lane use
Deforestation
Dan construction
Ground water abstraction
```
79
Over abstraction?
When water is taken from aquifers, ground water levels fall. If the amount of water taken is greater that the amount it water falling it is called over abstraction
80
Groundwater abstraction?
When water us taken out faster than it is replaced (from aquifers), causing reduced ground are flow and a lower water table
81
Dan construction?
Dams reduce downstream river flow and discharge, increased surface stores thus means more evaporation
82
Cloud seeding?
This is in an attempt to change the amount of precipitation by dispersing substances into the air that serve as cloud condensation nuclei
83
Urbanisation?
Creates impermeable surfaces that reduces infiltration and increases surface runoff and through flow via artificial drains: river discharge increases as a result
84
What are 4 impacts on drainage basin due to reservoir construction?
Reduce river flow bellow the, leading to loss of vegetation
They abstract water from the drainage basin
Salinity levels can rise as water evaporates
In tropics, mats of floating plants on water surface makes evapotranspiration rates 6x higher than in open water
85
Water budget equation?
Precipitation= channel discharge + evapotranspiration + change in water storage
86
5 ways in which the Amazon forests can effect the hydrological cycle?
Risks to wildlife
Risks indigenous tribal communities
Precipitation can arrive in bursts causing floods
Affect water supplies of Brazilian cities
Winds blowing over uneven forest canopy creates turbulence, which allows atmosphere to absorb moisture
87
What does the water budget give a direct comparison to?
Natural water supply and demand- can identify a positive water balance and when there is a drought risk
88
What are the 6 characteristics on a soil moisture budget graph show?
```
Soil moisture surplus
Soil moisture utilisation
Maximum annual temp
Soil deficiency
Soil moisture recharge
Field capacity
```
89
Soil moisture surplus
Precipitation is greater than evaporation thus meaning the soils moisture increases
90
Soil moisture utilisation
As temp increases, so does evaporation. The soil uses the moisture gained during its surplus, used up by plants etc
91
Maximum annual temp
The point of maximum evaporation= highest risk of drought. Soil moisture is now used up. Precipitation likely to be used up, no run off, river levels will fall
92
Soil deficiency
Despite evaporation decreasing, there is not enough precipitation to provide for vegetation. Plants must adapt to survive
93
Soil moisture recharge
Occurs when potential evapotranspiration decreases so that it is lower than precipitation, soil begins to fill again
94
Field capacity
Soil moisture is now full, additional rainfall will relocate to the water table and groundwater stores will be recharged
95
What slowly feeds the river system?
Groundwater during between periods of rain
96
Simple river regime?
Seasonal variation in regime- periods of high discharge followed by low discharge (glacial melt water and monsoons) cause sudden fluctuations in river input
97
Complex regime?
Tend to occur for larger rivers that cross different reliefs and climactic zones thus experience different climactic effects eg Ganges
98
What are 7 characteristics affecting the characteristics of a river regime?
```
Channel capacity
Vegetation
Area and relief of drainage basin
Climate
Volume, pattern and intensity of precipitation
Geology of soil
Anthropogenic factors
```
99
What are the 5 characteristics on a hydrography?
```
Rising limb
Peak flow
Lag time
Falling limb
Base flow
```
100
What limb on a flashy storm hydrography is always steeper?
Rising limb
101
Rising limb?
The increase of river discharge, not instantaneously after precipitation
102
Peak flow?
The maximum discharge, delayed after maximum precipitation has occurred
103
Lag time?
The tine delayed between peak rainfall and the peak discharge
104
Falling limb?
As the storm precipitation levels decrease, discharge will in turn decrease over time
105
Base flow?
Eventually, the discharge will return to a normal level
106
Flashy storm hydrograph?
Means that the graph depicts sharp vertical jumps and equally steep vertical declines.
107
5 features of a flashy storm hydrography
```
Short lag time
High peak
Low infiltration rate
Urbanised
High water table
```
108
Subdued storm hydrograph?
'Delayed', or 'flat' hydrographs
109
5 features of a subdued storm hydrograph
```
Long lag time
Low peak
Gently sloping rising limb
High infiltration rate
Low water table
```
110
What does SUDS stand for?
Sustainable drainage systems
111
What is an example of a SUDS?
Permeable pavement, green roofs
112
Drought?
A period of deficit rainfall
113
What are the 4 types of drought?
Meteorological
Agricultural
Hydrological
Socio economic
114
Meteorological drought?
When longer term precipitation is much lower than normal
115
Agricultural drought?
When there is insufficient soil moisture to meet the needs of crops
116
Hydrological drought?
When there are deficiencies in surface and sub surface water supplies eg rivers
117
Socio economic drought?
When the water demand from people and industry exceeds water availability
118
What type of hazard is drought?
Hydro-metrological hazard
119
What results in shortened seasons and severe droughts?
When the ITCZ does not show up, blocked by stable high pressure
120
El nino?
The appearance of warm surface water from time in Eastern equatorial pacific ie a warmer event
121
La nina?
The appearance of colder than average sea surface temperatures in the central and East equatorial pacific ie a colder event
122
The southern oscillation?
Is a see-saw of atmospheric pressure between the pacific and Australia area
123
The southern oscillation index?
Represents the difference in average air pressure measured at Tahiti and Darwin, Australia
124
What are the two main causes of drought?
Climactic Variability
| El ninio
125
What enhances the causes and effects of drought?
Climate change
126
Desertification?
Once productive land gradually changing into a desert like landscape
127
How are humans increasing desertification process?
Via positive feedback
128
Positive feedback?
Enhances or amplifies change, moving a system away from its equilibrium state and making it more unstable. It creates a 'snowball effect'.
129
Negative feedback?
Decreases the amount of change by reducing some of the inputs, returning the system to stability.
130
What is the greatest environmental challenge and how many people are affected by this?
Desertification
| 2 billion people
131
What are the two ways in which humans can increase drought risk?
Direct (reservoir construction)
| Indirect (climate change)
132
What are the three main causes of desertification?
Animals grazed in higher numbers to feed people
Ground is farmed more intensely
Reduction of forest cover and vegetation (exposed ground)
133
How does climate change impact the environment?
Making temperature hotter and rainfall less reliable
134
What is the desertification process?
No plants or leaves intercept the rainwater and soil is left to exposed sun which bakes the ground. Rainwater does not soak in soil so it degrades losing fertility and structure.
135
What does drought result in?
Famine
Migration
Terrorism etc
136
Impact of drought on rainforests?
Younger trees die, reducing the canopy cover
| Tree litter can catch fire due to being exposed to tropical sun = wildfires
137
Impact of drought on wetlands?
Increase tree mortality= less animal habitats
Wildfires
Reduces cattle ranching
138
Two main meteorological causes of flooding?
Intense rainfall
| Prolonged, heavy rainfall
139
What can meteorological processes increases?
Increases inputs in hydrological cycle causing a surplus of water in system
140
What does an increase of inputs in the hydrological cycle cause?
Freshwater floods
141
How much of the lands area does freshwater flooding affect?
1/3 of land's area
142
What do most freshwater floods result from the presence of?
Low atmospheric pressure systems
143
What are the three main factors that cause flooding within a low atmospheric pressure system?
Intense monsoonal rainfall
Rapid snow or ice melt
Prolonged and heavy rainfall associated with passage of depressions
144
Intense rainfall characeristics?
Severe thunderstorms= convectional rainfall
| Channel capacity is quickly exceeded resulting in flash flooding
145
Prolonged, heavy rainfall in the mid latitudes?
Come in the form of depressions
146
Prolonged, heavy rainfall in the sub tropics?
During the wet phase of a monsoon
147
Depressions?
An area of low pressure. Air rises in a depression so clouds and rainfall are formed. Depressions therefore bring unsettled weather and rain. Winds are normally stronger.
148
Where do depressions form?
Over the Atlantic Ocean and are carried across Britain by westerly winds.
149
What is the main reason for the UKs changing weather?
Depressions
150
Monsoon?
A seasonal reversal in wind direction. Brings prolonged, heavy rainfall
151
Water scarcity?
Renewable water resources are between 500 and 1000m
152
Absolute water scarcity?
Renewable water resources are very low: bellow 500m per capita
153
Renewable water resources?
The long term annual average total of internal and external renewable water resources?
154
What is the link between water and human causes of water stress?
Human factors increase outputs or degrade supplies
155
What is the link between water and physical causes of water stress?
Lead to reduced inputs
156
What are the two main physical causes of water stress?
Climate variability
| Saltwater encroachment
157
What are the three main human factors that can lead to water stress?
Over abstraction
Industrial pollution
Agriculture
158
How can climate variability lead to water stress?
In warmer climates= increased evaporation and transpiration = less precipitation
Higher water temp can encourage bacteria growth
159
How can saltwater encroachment lead to water stress?
Global sea level rise, localised groundwater abstraciona and thermal expansion are all enhancing risks of saltwater encroachment
160
How can over abstraction lead to water sress?
Too much water is removed from groundwater to that supplies diminish
161
What % of the worlds aquifers are exploited?
20%
162
How can industrial pollution lead to water stress?
Waste and chemicals are released into the water supplies
163
How can agriculture lead to water stress?
Excessive water withdrawals (inefficient use= depleted aquifers and habitats)
Chemical fertilisers can get into water supplies
164
What are the two main processes operating within the hydrological cycle on a global and local scale?
Rain
| Snow
165
Biosphere?
Made up of the parts of Earth where life exists—all ecosystems
166
Why could the hydrological cycle be possibly viewed as an open system?
Due to the input of solar energy which drives fluxes and flows
167
Why is the hydrological cycle a closed system?
There are no losses or gains of water over time
168
What % of the worlds water is freshwater?
2.5%
169
Blue water?
Water in our surface and groundwater reservoirs ( river, lakes)
170
What % of freshwater is accessible to us in the form of blue water ?
0.3%
171
What are three of the main contributing factors to unequal water distribution?
Climate, demand, human development and population growth
172
What impact do human activity have on the water distribution system?
Can cause local water shortages due to the transfer of water between different parts of the system
173
What % of water do human withdraw of the worlds annual freshwater runoff?
8%
174
What % of the 8% freshwater withdrawal is used for irrigation?
7%
175
What % of water returns to the atmosphere after being used for irrigation?
6.3%, the rest runs as grey water
176
Grey water?
Partly degraded/polluted water- bathtubs, showers, sinks, washing machines
177
What % of water returns to the atmosphere after being used for industrial activity?
0.6%
178
What % of water returns to the atmosphere after being used for industrial activity?
0.12%, the rest runs as grey water
179
What % of water returns to the atmosphere after being used for domestic and commercial use?
0.4%
180
What % of water returns to the atmosphere after being used for domestic and commercial use?
An equal amount is evaporated and lost via runoff, some runs as black water
181
Black water?
The mixture of urine, feces and flushwater along with anal cleansing water
182
What type of water stores have short turnover times?
Renewable water stores
183
What type of water stores have much longer turnover times?
Non-renewable water stores
184
Turnover time?
measure of the movement of an element (water) in a biogeochemical cycle
185
What are the three main ways humans can increase flood risk?
Urbanisation
Agricultural development
Mismanagement of rivers
186
Agricultural development?
Farming upstream of urbanised floodplains can result in flooding downstream: soil compaction and deforestation
187
Mismanagement of rivers?
Straightening channels in urban areas can result in flooding: increase discharge and the natural channel may not be able to cope
188
Channelization?
Straightening the river channel
189
How do you measure the flood frequency?
Calculated by observing how often a flood of a certain magnitude occurs in a given .location or time period
190
What is flood frequency expressed in?
Return periods or recurrence intervals e.g. A 1 in 100 year flood meaning the flood magnitude is only to occur once in an 100 year period
191
Return periods?
An average based on historical data (flood magnitude), it gives the estimated time interval between events of a similar size or intensity.
192
What does IPCC stand for?
Intergovernmental panel on climate change
193
What does the IPCC predict regarding climate change?
That increasing greenhouse gas concentrations will have a considerable impact on the global hydrological cycle
194
Globally, what is there an increase of?
Precipitation intensity
195
What does the increase of precipitation intensity due to climate change result in?
A depletion of stores and a faster hydrological cycle- a wetter atmosphere
196
What will changes in run off due to climate change result in?
Less water stored as groundwater
Rapid snow melt= flashy flooding
Some regions will experience limited runoff
197
In terms of drought, how will this worsen due to climate change?
Greater level of evapotranspiration and limited amount of surface storage
198
How unequal is the worlds water supply?
Proportion of worlds water that is accessible for human is very small: 1%- not equally distributed and demand is too high
199
What does the water availability gap refer to?
How water is not equally distributed and demand is too high
200
In terms of water distribution, what country factors are important?
Physical geographical factors such as climate and development level such as affluence and population size
201
What % of water is contained in just 10 country?
60%
202
What % of worlds population live in areas receiving only 25% of worlds annual rainfall?
66%
203
How much has water usage increased between the years of 1900-2000?
85%- set to increase further
204
What are the three main causes that impact the water availably gap?
Diminishing supplies
Rising demand
Competing demand from users
205
What are some examples of rising demand that impact water supplies?
Population growth
| Economic development
206
What are some examples of diminishing supplies that impact water supplies?
Impact of climate change
Deteriorating quality from the population
Water pressure point/ water hotspot= supplies under threat
207
What are some examples of competing demand from users that impact water supplies?
Internal conflicts in a basin
| International issues upstream and downstream
208
Main PHYSICAL factors affecting water supply?
Topography
Geology
Climate x precipitation
River systems
209
The physical factors affecting water supplies on a regional scale?
Geology
Topography
Snow fall and glaciers
River systems
210
The physical factors affecting water supplies on a global scale?
Climate
211
How does climate affect water supplies?
Precipitation varies across different climates: mid lat receives most rainfall
Seasonal and highly variable
212
How does topography affect water supplies?
Areas with high relief generally get more precipitation and surface runoff is greater for more inclined planes, so channel flow tends to be larger so water can be easily stored in dams and reservoirs
High relief allows for cryosphere storage
213
How does geology affect water supplies?
Controls the distribution of aquifers and groundwater storage- permeable rocks can be infiltrated, water can be stored easily underground
214
Why is geology important in terms of groundwater?
Groundwater regulates flows and provides an even supply of water throughout the year, provided natural recharge can keep up with abstraction
215
How does river systems affect water supplies?
Are important for regional water supplies- a significant source of water for multiple counties
216
How do snow and glaciers affect water supplies?
Their seasonal thaw feeds into river systems.
217
How does the global atmospheric pressure system play a big role in water security?
Makes the mid lats and equatorial regions water secure
218
When does water scarcity occur?
When there’s less than 1000m cubed per capita of water available
219
What % of the worlds counties face physical scarcity, where more that 75% of their blue water flows aren’t being used?
2.5%
220
By 2050. what % of people will be experiencing water scarcity?
1.5 billion people
221
Economic water scarcity?
Don’t have enough money to invest in new technology, lack of governance etc
222
What is water still scarce in countries with satisfactory physical availability?
Poor management
Privatisation
Gov corruption
223
Human factors that affect water supply?
```
Pollution
Industrial pressure
industrial activity
Over extraction
Saltwater encroachment
```
224
As a direct result of limited supply, what has happened to price of water?
Price of clean water has increased
225
What does the increase in the price of water affect?
The access of water
226
Four sustainable ways to manage the drainage basin?
Growing vegetation on roofs- increase interception
Create permeable pavements- increase infiltration
Rainwater harvesting- collecting rainwater
Creating wetlands- act as natural sponges in
227
What are the impacts of allowing human development on a basin to occur?
Deforestation, tree felling and slash-and-burn- soil erosion and more surface runoff
Impermeable surfaces- more surface run off
Bridges can act as dams on some rivers- restricts channel flow
Drainage and sewage systems will reduce lag time- flash flooding risks
228
How does wet lands act as temporary water stores within the hydrological cycle?
Act as giant water filters which traps and recycles nutrients and pollutants which maintains water quality
