Water Flashcards
(127 cards)
1
Q
What are the two forms of energy that drive the hydrological cycle?
A
Gravitational potential energy.
Solar energy (changes in state and wind direction).
2
Q
What % of total global water budget is stored in oceans and what is the average residency time?
A
97%
3600 years
3
Q
What % of total global water budget is stored in the cryosphere and what is the average residency time?
A
1.9%
15000 years
4
Q
What % of the world’s water is freshwater?
A
2.5%
5
Q
What is the difference between green water and blue water?
A
Blue - amount of rainfall that enters lakes, rivers and groundwater
Green - amount of rainfall that is intercepted or taken up by vegetation and evapotranspired.
6
Q
What is ablation?
A
Loss of water stored in ice through melting.
7
Q
What are the 3 types of rainfall?
A
Orographic
Frontal
Convectional
8
Q
Describe orographic rainfall.
A
Humid air forced to rise over mountains. Air cools, condenses, clouds, gravity, rain. Most rain falls on slopes facing wind direction. Rain shadow effect on other side.
9
Q
Give an example of where there is a rain shadow effect.
A
Eastern side of the UK receives less than the West due to the Western hills causing orographic rainfall.
10
Q
Describe frontal rainfall.
A
Warm humid air forced to rise at a low pressure system (warm or cold front). Air cools, condense and forms clouds.
11
Q
Describe convectional rainfall.
A
Ground and lower atmosphere heated by solar energy causing rising thermals of air. Rise, cool and form cumulo-nimbus clouds followed by thunderstorms and intense heavy rainfall.
12
Q
What is the water table?
A
The boundary between soil surface and where the ground becomes saturated with water.
13
Q
What is interception?
A
Layer of vegetation intercepting water before it reaches the ground. Proceed to stem and drip flow to the ground.
14
Q
What is infiltration?
A
The downwards movement of water through soil (entering topsoil).
15
Q
What is percolation?
A
The downwards movement of water through permeable or porous rocks.
16
Q
What is throughflow?
A
Lateral (ish - it has to be downhill) movement of water through the soil but above the water table.
17
Q
What is base flow (or groundwater flow)?
A
Downwards or lateral movement of water below the water table that eventually seeps into a river channel.
18
Q
What is channel flow?
A
The volume of water contained within a river channel (discharge).
19
Q
What is surface runoff?
A
Rain falling onto the ground flows over the surface because there is no time to infiltrate, ground is frozen or saturated or on impermeable surfaces.
20
Q
Which water stores are considered non-renewable?
A
Fossil water
Much of the cryosphere
21
Q
What is a drainage basin?
A
An area of land drained by a river and its tributaries (river system).
22
Q
What is a watershed?
A
A high ridge of land marking the edge of a drainage basin.
23
Q
What is a confluence?
A
When two or more flowing bodies of water join together to form one channel. Basically a tributary joining the main river channel.
24
Q
Identify 5 physical factors that influence drainage basins.
A
Climate
Vegetation
Soils
Geology
Relief
25
Identify 4 human actions that impact drainage basins.
Deforestation
Urbanisation
Reservoir creation
Abstraction of water.
26
How much of the Amazon rainforest has been lost?
17%
27
What amount of water did the Amazon release into the atmosphere?
20km3
28
What reduction in rainfall is expected in the Amazon by 2050?
21% reduction
29
What is a water budget?
A balance between precipitation, evaporation and runoff. It is a tool to access availability in an area over a specific period of time.
30
What is a water surplus?
Positive water balance (inputs>outputs).
31
What is a water deficit?
Negative water balance (inputs
32
What do water balance graphs show?
Balance between inputs (precipitation) and outputs (potential evapotranspiration) of water across a year.
33
What occurs during soil moisture utilisation and when does it occur?
Potential evapotranspiration exceeds precipitation - dry season. Soil moisture is used by plants or lost by evapotranspiration.
34
What occurs during soil moisture recharge and when does it occur?
Precipitation exceeds potential evapotranspiration - beginning of wet season. Moisture in soil is replenished.
35
What is the term for when the soil moisture is saturated and water now begins to recharge groundwater stores in the water table?
Field capacity.
36
Describe the water budget throughout the year in a tropical northern hemisphere climate.
Brazil transpiration rates consistent throughout year due to consistent temperature. Highest rainfall in winter (Feb) moisture surplus until May. May-Nov rainfall much lower, deficit by oct.
37
Describe the water budget throughout the year in a temperate northern hemisphere climate.
Southern UK similar precipitation all year with slight dip in summer. High evapotranspiration summer very low evapotranspiration winter. Deficit in July and August.
38
What are on the axes of river regimes?
Discharge, months.
39
What are simple river regimes?
A river that experiences periodically high followed by low discharge.
40
What typically causes simple river regimes?
When inputs depend on glacial meltwater, snowmelt or monsoons.
41
Give an example of a simple river regime.
River Rhône in the alps (France Switzerland). Large peak at end of winter due to snowmelt.
42
What are complex river regimes?
Rivers cross several different reliefs and climatic zones (or even human factors), therefore experiencing the impacts of multiple different climate events.
43
Give an example of a complex river regime.
The Yukon river in Alaska and Canada. Tundra and mountain biomes. Snowmelt = massive peak May-June. Decreasing discharge during winter due to reduced, frozen precipitation. Subarctic climate causes differing precipitation in different ares. Human influences include HEP, farming and water abstraction. Considered complex due to 850km2 drainage basin with many different inputs that can vary.
44
Describe influences on the Nile's complex river regime.
2 tributaries - White and Blue Nile. Blue Nile more pronounced flood season than White. Flood season June-Aug, dry season Oct-May. Precipitation decreases as Nile travels north, reducing discharge. Aswan high dam (Egypt) reduces peak in flooding season to increase discharge in dry season.
45
What is the lag time on a storm hydrograph?
Time interval between peak rainfall and peak discharge.
46
What terms are used to refer to the sections of the storm hydrograph where discharge is increasing and decreasing?
Rising and falling limb.
47
What are the two types of storm Hydrograph?
Flashy and low/flat.
48
What shape and size of drainage basin would create a flashy storm hydrograph?
Small and circular.
49
What is drainage density and how does it impact storm hydrographs?
The number of surface streams per Km2. High drainage density means water will reach the river faster, causing flashy storm hydrographs.
50
Give the UN definition of drought.
An extended period of time (relative) of deficient rainfall relative to the statistical multi-year average for a region.
51
What are the 3 types of drought?
Meteorological - degree of dryness compared to normal precipitation
Agricultural - insufficient water for farming
Hydrological - drainage basin deficiencies
52
Identify a short-term physical cause of drought.
Mid-latitude anticyclone blocking. Polar Front Jet Stream moves northwards. Subtropical high pressure zones move northwards bringing stable, calm, hot weather e.g. UK 2018.
53
What is an anticyclone?
Area of high pressure where air moves apart and sinks. Clockwise winds in Northern hemisphere.
54
What term is used to describe the changing conditions in the Pacific?
El Niño Southern Oscillation (ENSO).
55
Describe normal conditions in the Pacific.
Trade winds East to West. Upwelling of cold water East (South America). Warm collection of water West (Australia). Australia experiences more evaporation & rainfall.
56
Describe conditions in the Pacific during an El Niño event.
Weaker/reversed trade winds. Upwelling West, warm water East.
57
What are the conditions in South America caused by El Nińo?
Drought in parts - especially West coast. Flooding due to rainfall in Brazil, Argentina.
58
What are the conditions in Australia caused by El Niño?
Typically drier and warmer (drought) with changing precipitation patterns and less tropical cyclones.
59
Describe conditions in the pacific during La Niña.
Stronger east to west trade winds. Upwelling East increases and warm water pushed further west around Aus.
60
What are the conditions caused by La Niña in South America?
Drought on west coast but flooding in Brazil.
61
What are the conditions caused by La Niña in Australia?
Low pressure zones cause intense rainfall in western Pacific.
62
Give a case study for the impact of ENSO.
Northern Australia flooding 2010. Queensland worst floods in history: 10,000 evacuated and >$2bn in damages.
63
What impacts does ENSO have around the world?
El Niño generally increased average global temperature, La Niña opposite. Impacts global precipitation patterns through global atmospheric circulation. E.g. La Niña better monsoon season in monsoon-reliant India & Bangladesh.
64
Identify 2 long-term natural causes of drought.
Global atmospheric circulation.
Climate change.
65
Explain how global atmospheric circulation causes drought.
Descending air between Hadley & Ferrel and between Polar cells - high pressure creating hot and cold deserts respectively. Very low rainfall levels common and impacts areas nearby when cells may shift slightly.
66
What is the best example of climate change causing drought?
Intertropical Convergence Zone (ITCZ) blocking.
67
Explain how blocking of the ITCZ causes drought.
High pressure zone associated with descending parts of Hadley cell block movement of ITCZ. Prevents rainy conditions (trade winds meeting, high temp, air rising, low pressure) travelling north to provide Sahel region with monsoons.
68
How does climate change influence the high-pressure subtropical ridge? Give a case study.
Strengthens it. 1997-2009 80% reduction in rainfall in South-East Australia due to strong high pressure belt and continued El Niño events.
69
What impact have humans had on the Aral Sea in Kazakhstan and Uzbekistan?
90% reduction in water volume since 60s (10x more saline).
70
What caused the Aral sea volume to decline?
Soviet Union divert both tributary rivers to dry areas of Asia for agriculture (cotton). Without supply (rain shadow effect and desert) evaporation diminished size.
71
What were the impacts of the reduced Aral sea volume?
Destroyed fishing industry. 24 fish species dead. Dust storms blow salt, pesticides into villages causing respiratory illness.
72
What has been happening in the Sahel region since the 1960s?
Declining amounts of rainfall. Severe case 2011-12.
73
What are the 2 human causes of drought in the Sahel region?
Anthropogenic climate change. Higher sea surface temp. Less rain-carrying winds over Sahel from Atlantic.
Atmospheric cooling due to Western air pollution. Causes ITCZ to stop travelling northwards.
74
What are the impacts of the Sahel droughts?
Highest poverty rates, lowest development levels, highest population rates globally. Overgrazing, over-cultivation, desertification. More drought vulnerability (+ feedback loop) self-perpetuating severe droughts.
75
How long does it take for a living tree to fully recover from a drought?
Two to four years.
76
Where did severe drought and abnormally high temperatures lead to 90% death of Piñon Pines (in areas)?
Four Corners region of the South-West USA.
77
What caused the death of so many Piñon pines in the Four Corners region?
Hot dry conditions made pines exceptionally vulnerable to bark beetle outbreaks and attacks.
78
How much carbon do forests store?
0.73 tonnes of carbon per hectare per year on average.
79
What are the impacts of droughts on wetlands?
Areas of open water shrink or dry up - loss of habitat. Soil erosion. Reduced ability to store water in times of flood (increasing flood risk). Organic soils oxidise, releasing CO2. Impact on ecosystem e.g. less aquatic birds.
80
What is the term for a glacial outburst flood that occurs when the dam containing a glacial lake fails?
Jokalhlaup.
81
Identify different meteorological causes of flooding.
Intense storms
Heavy rainfall
Monsoon rains
Snowmelt
Prolonged rainfall (multiple low pressure systems).
82
Identify other potential physical causes of flooding?
Relief
Temperature
Rock type
83
Explain how deforestation increases flood risk. (2 ways)
Reduces interception and evapotranspiration - more surface runoff, flashy hydrographs.
Increased soil erosion increases sediment load in river and deposition within channels. Reduces capacity, increasing chance of bursting banks.
84
Explain how urbanisation leads to increased flood risk.
Expansion of impermeable surfaces and drainage systems - surface runoff and reduced lag time.
Control of river's path reduces its capacity.
85
What have been introduced in urban areas in an attempt to offset the increased risk of flooding?
SuDS - Sustainable Development Systems.
Green roofs, permeable pavements and rainwater harvesting.
86
Explain how flood mismanagement increases flood risk.
Building embankments reduces flood risk in immediate area. Transfers discharge to unprotected areas or chokepoints downstream, increasing risk there.
87
What were the causes of the 2015-16 floods in the UK (north England).
Sequence of low pressure systems (depressions). Each brought periods of prolonged intense rainfall.
Storm Desmond (Cumbria) months rain in one day (combination of convectional, orographic and frontal rainfall).
Polar front jet stream abnormally low (La Niña).
15% cut in flood defence budget since 2000.
88
How many homes were flooded in UK 2015-16 storms?
16,000
89
What were the total estimated economic costs of the 2015-16 floods in the UK?
£5bn.
90
Identify some more impacts of the 2015-16 UK floods.
Massive disruption (roads (M1), railway, services e.g. healthcare).
7 death toll. Evacuations.
River washed away.
Flood defence failure.
91
Why is climate change predicted to cause greater precipitation intensity over land areas across the world?
Lower atmosphere warming - evaporation rates increase = more moisture in lower atmosphere. Greater cloud density = more intense rain.
92
What impact will climate change have on runoff around the world?
1 degree celsius rise could lead to 40% increase in runoff. Accelerated hydrological cycle with more intense rainfall leads to less infiltration and greater runoff (increasing flood and drought risk - less groundwater stored).
93
Explain the impact of climate change on the cryosphere.
Permafrost degradation in northern areas. Earlier snowmelt and less snow as precipitation proportionally. Retreating glaciers since 1800s.
94
What will the impact of climate change be in the Mediterranean?
30% reduction in rainfall. 20% above average increase in temperature compared to average global levels. Drought risk may be 10x worse.
95
What will the impact of climate change be in India, Pakistan and Bangladesh?
Longer dry season periods followed by more intense monsoon seasons (La Niña more intense and increased evaporation).
96
Why is demand for water rising?
Population growth
Rising standard of living
Economic growth
Irrigation due to extensive agriculture
97
Name physical causes of water insecurity.
Climate change
ENSO
ITCZ blocking
Changes in glacial/snowmelt
Flooding
Reduced groundwater storage
Less precipitation
98
Name human causes of water insecurity.
Climate change
Dams and reservoirs
Deforestation
Pollutants in water sources
Population increase
Economic development
Irrigation
99
Define water insecurity.
When people do not have enough quality water to sustain livelihoods, human wellbeing and socio-economic development.
100
Define water stress.
When annual water resources are between 1000 and 1700 m3 per person causing restrictions and tensions.
101
Define water scarcity.
Annual water resources less than 1000 m3 per person causing conflict and overuse of reserves.
102
Describe the difference between physical and economic water scarcity.
Physical - lack of available freshwater resources (semi-arid areas).
Economic - Access to water resources limited by poor management, lack of financial ability to develop water resources, affordability.
103
How does water stimulate economic development?
Energy production for energy security
Manufacturing for industry
Economic confidence for FDI
Farming for food security
104
What 5 factors does the Water Poverty Index assess?
Environment
Resources
Access
Capacity
Use
105
What does a low WPI score indicate?
Greater amounts of water poverty.
106
What two factors can cause salt water encroachment?
Over-abstraction of freshwater
Sea level rise
107
Name causes of the Karachi water crisis in Pakistan.
Rapid urbanisation (infrastructure problems)
Climate change (extended dry periods followed by extreme monsoons)
Corruption
Salt water encroachment (over-abstraction)
108
What are the impacts of the Karachi water crisis?
Black market for water (gang activity and illegal selling by water board).
Cheaper to buy 2nd hand clothes than buy water to wash them.
Massive water inequality.
109
Why is there potential for massive water conflict around the world?
UN estimates 40% of the world's population relies on transboundary water supplies. Over half of these have no international agreement yet.
110
Why is water conflict around the Nile likely?
Shared by 11 semi-arid countries. Supplies increasingly under pressure from economic development, population growth and climate change.
111
What happened in 2010 and 2015 that Egypt and Sudan were very opposed to?
New agreements allowed upstream countries greater access to the water. Historically supplies were controlled by Egypt and Sudan. 2015 agreement enabled building of Grand Ethiopian Renaissance Dam.
112
Impacts of the Grand Ethiopian Renaissance Dam.
Energy security, water for irrigation industry and domestic use, economic development.
Controlled flooding for downstream countries.
Changes in sediment flow.
Reduced water security for Egypt and Sudan - Geopolitical tensions.
113
What hard engineering schemes has China used to manage water?
Three Gorges Dam
South-North Water Transfer Project
114
Why did China require such extreme methods of water transfer?
North-east China water scarcity due to large cities, overuse in farming and pollutants in water sources. Most of China's water is in the south.
115
Explain how the water management in China works.
Three Gorges Dam stores surplus that can be transferred north. Over 25bn m3 freshwater transferred 1000km from Yangtze river basin per year.
116
Identify drawbacks of water management in China.
1.3 mil people displaced for Dam, further 300,000 for transfer project.
Extremely expensive.
May be too expensive for farmers.
Industrial routes means pollution (more purification needed).
Does not solve overuse of pollution of water.
May reduce water security in the south.
117
What % of water in Israel is desalinated?
85%
118
What are the drawbacks of the 5 desalination plants built in Israel in 2013?
Produce vast amounts of salt/brine with anti-scaling agents that harm ecosystems.
Each requires its own energy plant, but these are mostly solar.
119
How else have Israel managed their very limited water supply?
Stringent conservation techniques
Smart irrigation
Recycling sewage water for agriculture
'Real value prices' for water
Imports from Turkiye.
120
Why would Singapore normally be at risk to water insecurity?
City state with high population density.
121
Singapore imported 80% of its water from Malaysia before 2010, what has it done to reduce these imports?
Massively improve efficiency - 5% leakages compared to UK's 20%.
Water prices scaled (overuse = gets more expensive but subsidies for those that can't afford it.
Educating the public.
Ultra-efficient local catchment (drains, rainwater harvesting etc).
NEWater recycling water scheme.
Desalination.
122
Why is management of the Colorado river threatened, especially in California?
Climate change - 10% reduction in rainfall last 30 years.
Provides water to 7 US states and Mexico.
Farming uses vast proportion of water.
Increasing populations.
Large part of basin is arid / semi-arid.
123
What action has been taken to manage water usage in the Colorado basin?
2007 agreement between US states to divide water usage, reducing California's usage.
Later, US-Mexico deal to allow Mexican water storage in US, improving their infrastructure, any surpluses used by US.
Domestic conservation - improving efficiency, drought tolerant plants
Smart irrigation
Re-using wastewater.
124
Assess the effectiveness of the Colorado management scheme.
Reduced geopolitical tensions.
Greater equality achieved.
Demand NOT reduced (unsustainably high).
Storage and channel flow still depleting.
125
What have the UN to manage and reduce water conflict worldwide?
UN convention on the law of the non-navigational uses of international watercourses. Rules on equitable and reasonable use of water without harming neighbouring countries.
126
Give an example of an agreement made by the UN convention on the law of the non-navigational uses of international watercourses.
Nile River Basin Framework (10 countries) is managed, monitored, rules enforced and allocations made.
127
Evaluate the success of global treaties and the UN convention on the law of non-navigational uses of international watercourses.
Difficult to implement. 150 treaties made but 37 violent conflicts so far.
