Theme 3 - 3.6 - Water Flashcards
Define water supply.
The provision of water by public utilities, commercial organisations or by community endeavours.
Define dam.
A barrier that holds back water.
Define reservoir.
An artificial lake primarily used for storing water.
Define wells and boreholes.
A means of tapping into various types of aquifers, gaining access to groundwater.
Define potable water.
Water that is free from impurities, pollution and bacteria, and thus is safe to drink.
Define water stress.
When water supply is below 1700 cubic metres per person per year.
What are some different methods of water supply?
- Reservoirs/Dams
- Wells
- Boreholes
- Desalination
- Aquifers (+ wells)
- Rivers/Lakes
What are some advantages and disadvantages of reservoirs/dams for water supply?
ADV.
• Stores water during prolonged periods of rain
• Water can be used to generate HEP
DIS.
• Expensive to build
• Building dams can flood areas
• Eroded material is trapped by the dam, reducing fertility of land downstream
• Water is lost in hot countries due to evaporation
What are some advantages and disadvantages of rivers/lakes for water supply?
ADV. • No construction needed • Can be used for other activities DIS. • Risk of flooding • Rivers don't trap water during heavy rainfall • Are easily polluted
What are some advantages and disadvantages of desalination for water supply?
ADV. • It preserves fresh water supplies • Not dependent on changing factors (e.g. weather) • Proven method which is scientifically backed -> Reliable DIS. • Plants are expensive to build • Expensive process • Requires lots of energy
What are some advantages and disadvantages of wells and bore holes for water supply?
ADV. • Self-sufficiency • Cheap DIS. • Easily contaminated • Danger of falling in
What are the main sources of water around the world?
Lakes and rivers
Describe the global water crisis.
- Lack of water is a constant threat in about 80 countries, with 40% of the world’s population.
- Demand for water is doubling every 20 years
- In poor countries, water supplies are often polluted
What are on-channel and off-channel reservoirs?
On-channel: Dam built across an existing river
Off-channel: Natural and human dug depressions which hold water
What is an aquifer?
An underground layer of water-bearing permeable rock, from which water can be extracted.
How is what extracted from an aquifer?
Wells are used.
In the 20th Century, what allowed water consumption to rise?
The building of many new dams.
Why are not many new dams being built as what can be done instead?
The best locations are already taken or are strongly protected. Instead, existing dams can sometimes be made higher to increase the reservoir capacity.
How much of the world water supply do aquifers account for?
Drinking water - 50%
Industry - 40%
Irrigation water - 30%
What is water from a well/aquifer known as?
Groundwater
How much of the UK water supply comes from groundwater (aquifers)?
35%
Where is groundwater (aquifers) most important?
Arid and semi-arid areas.
Where is desalination common and why is this possible?
- In the Middle East, where other forms of water supply are scarce.
- It is possible because waste gases from oil wells are used. Otherwise, it would be very expensive.
Why is desalination not very common?
It is expensive.
How does total water use change with development?
It increases.
Give some reasons why total water use is higher in MEDCs than LEDCs.
- More electricity has to be generated
- More industrial activity
- People can afford to use more water
Describe water use by type in LEDCs.
- Most used in agriculture
* Little used in industry and domestic use
Describe water use by type in MEDCs.
- Most used industry
- Less used in agriculture (but still can be a lot)
- More used for domestic use
Is water use in agriculture in MEDCs always low?
No, not always. There are exceptions such as the US, which use a large percentage in agriculture.
Does water supply depend only on precipitation amounts?
No, water supply is what matters. It could rain a lot, but there may be no way of collecting and storing this water, for example.
Describe the uneven precipitation in the world.
- Over 60% of the world population live in areas receiving only 25% of the world annual precipitation.
- Arid regions cover 40% of the world’s land area, but receive only 2% of global precipitation.
What are the two types of water scarcity?
- Physical water scarcity
* Economic water scarcity
What is physical water scarcity?
When physical access to water is limited
What is economic water scarcity?
When a population does not have the enough money to make use of a source of water.
Which regions usually suffer due to physical water scarcity?
Arid and semi-arid regions in the world.
Which regions usually suffer due to economic water scarcity?
Much of sub-Saharan Africa.
What are some reasons for water scarcity?
INCREASING DEMAND • Increasing population • Increasing agricultural, industrial and domestic use • Increased energy production FALLING SUPPLY • Climate change • Groundwater depletion • Pollution (due to sewage, etc.) • Deforestation -> Trees prevent excessive evaporation • Political issues + War • Mismanagement • Uneven precipitation distribution
What are some impacts of lack of access to clean water on local people?
- Agricultural loss
- Famine
- Animals dying
- Loss of income
- Disease/Illness -> Death
- Children have to walk far to get water -> Can’t get education
- Sanitation issues (e.g. can’t wash)
What are the impacts of lack of access to clean water on economic development?
- Less water for agriculture and industry -> LEDCs reliant on agriculture
- Worker efficiency reduced -> Diseases and tiredness
- Tourism is reduced (people don’t want to visit that place)
- Higher cost of water mean people have less money to spend on other things which fuel the economy
- Production of water-intensive goods (e.g. cars) is reduced
- Limits production of biofuels
How can a lack of water lead to competition and conflict?
- In Yemen, 70-80% of rural conflicts are due to water-related disputes
- In 2012, in Kenya, over 100 people were killed in clashes between farmers and cattle grazers
- During drought, large companies fight over water
What are the two ways in which water conflicts may happen?
- Demand for water exceeds supply
2. Control over access and allocation of water may be disputed
How can water supplies be managed?
- More sustainable use (e.g. taking a shower instead of a bath)
- Increasing cost of water to encourage lower use
- Finding new ways to exploit alternative sources instead of those being depleted
- Piping water from areas with a surplus to areas with a lack
- Making sure that water supply is of good quality
- Making sure that broken pipes are mended
- Developing more efficient irrigation systems
- Educating people about water use
- Recycle water
What is sustainable water use?
Using water supplies whilst maintaining levels for use in the future.
Who’s responsibility is sustainable water use?
Both a national and individual responsibility.
