What does water deficit mean?
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What does water deficit mean?
Water deficit occurs when the demand for water is higher than the supply.
Define water surplus.
Water surplus is when there is a greater water supply than demand.
State the meaning of water stress.
Water stress occurs when the supply of water is below 1700 cubic meters per person per year.
What is the definition of water scarcity?
Water scarcity is when the supply of water is below 1000 cubic metres per person per year.
True or False?
Areas with the greatest water deficit include Australia, North Africa, the Middle East, Western USA, parts of South America, and India.
True.
These areas have the greatest water deficit due to low precipitation, high levels of evaporation, poor water management, and high demand from increasing population, industry, and agriculture.
What is the Water Exploitation Index?
The Water Exploitation Index is a measure of water stress, given as a percentage.
True or False?
Areas with a water surplus include North-east Brazil in the Amazon rainforest, Canada, parts of the northern USA, and Russia.
True.
These areas have a water surplus due to high precipitation, low evaporation rates, effective water management, and low demand from low population and low temperatures.
Give three reasons for the increase in global demand for water.
There are several reasons for increased global water demand, including:
Increasing population
Growth of industries which use large quantities of water
More appliances, such as washing machines, which use water
Greater use of water for homes and leisure activities such as: Washing cars, watering gardens, hot tubs, swimming pools and golf courses
Increased use of showers and baths
Growth of agriculture to feed the increasing population, particularly meat production, which uses more water
Why has the supply of water changed over the last 50 years?
The supply of water has changed due to:
Climate change has led to change patterns of precipitation
Reduced precipitation in some areas
Rainfall at unusual times of the year in other areas
Greater abstraction of water
The building of dams and reservoirs
What is the global water use by sector?
Global water use by sector is:
70% agriculture
20% industry
10% domestic
Define domestic water use.
Domestic water use refers to the use of water for household purposes such as toilets, cooking, cleaning, and washing.
True or False?
In developed countries, most water is used for industry.
True.
In developed countries, most water is used for industry, while in developing and emerging countries, most water is used for agriculture.
State the meaning of irrigation.
Irrigation is the artificial application of water to land or soil to assist in the growth of crops.
True or False?
Many people in rural areas of emerging and developing countries have access to piped water and are less cautious with water use.
False.
Many people in rural areas of emerging and developing countries do not have access to piped water and are more cautious with water use as a result.
What is water infrastructure?
Water infrastructure refers to the basic physical and organisational structures and facilities needed for water supply and treatment, such as water and sewage systems.
Why do developing countries use a lower percentage of their water for industry?
Developing countries use less water for industry because there is far less industry so the demand for water for industrial processes is low.
Why has the demand for water increased in developed countries?
In developed countries, water use is higher due to:
Improving living standards, people have more appliances/sanitation which use water
Increased use of water in leisure and tourism, water parks, and golf courses
Increased urbanisation
Increasing industry, water is needed for the production of goods and energy
Increasing agriculture, more water is needed for livestock and crop irrigation
What is most water used for in developing countries?
Most water (82%) is used for agriculture in developing and emerging countries.
What are the main causes of cholera, diarrhoea, and dysentery in developing and emerging countries?
The main causes of cholera, diarrhoea, and dysentery in developing and emerging countries are water pollution and limited access to treated water.
Define sanitation.
Sanitation refers to the provision of facilities and services for the safe disposal of human waste and maintenance of hygienic conditions.
What is water pollution?
Water pollution is the contamination of water bodies, such as rivers, lakes, and oceans, by substances that make the water harmful for humans, animals, or the environment.
True or False?
In the UK, approximately 25% of the water supply is lost to leaks due to old infrastructure.
True.
In the UK, over 3.17 billion litres of water, or 25% of the water supply, is lost to leaks due to old water and sewage pipes.
Define eutrophication.
Eutrophication is the excessive richness of nutrients in a body of water, frequently due to runoff from the land, which causes a dense growth of plant life and the depletion of oxygen in the water.
How does soil erosion cause a decrease in water quality?
Soil erosion leads to soil washing into water sources causing sedimentation which can impact people's health due to the chemicals contained in the soil.
True or False?
Deforestation reduces transpiration and, as a result, decreases precipitation.
True.
Deforestation reduces transpiration, which is the process of water vapour being released from plants, and as a result, decreases precipitation.
What is a drought?
Drought is a prolonged period of below average rainfall, leading to a shortage of water.
Define aquifer.
An aquifer is an underground layer of water-bearing permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt) from which groundwater can be extracted using a water well.
In 2023, how many people globally did not have access to safe drinking water?
In 2023, the UN estimates that about 2 billion people did not have access to safe drinking water.
What is desalination?
Desalination is the process of removing salt and other minerals from saline water (such as seawater) to produce freshwater for human consumption or irrigation.
Define the term reverse osmosis.
Reverse osmosis is a water purification technology when:
Seawater filtered at high pressure
Small tubes syphon off drinkable water
Saline solution left behind is pumped back to the sea
What is distillation?
Distillation is a process of separating the components or substances from a liquid mixture by selectively boiling and then condensing the desired component. To distill seawater it is boiled, the steam is then condensed leaving the salt behind.
True or False?
Desalination plants are expensive to build and maintain, so they mainly operate in wealthy countries in water-stressed regions.
True.
Desalination plants are expensive to build and maintain, so they mainly operate in wealthy countries in water-stressed regions, such as Saudi Arabia, Oman, UAE, Australia, and the USA.
Define the term stakeholder.
A stakeholder is an individual, group, or organization that has an interest or concern in a particular issue or decision, and can be affected by or can affect the outcome.
Where does most of the water supply for Las Vegas come from?
About 90% of the water for Las Vegas comes from Lake Mead, the reservoir behind the Hoover Dam.
What are two opposing Las Vegas residents' views about water use?
Two opposing views of Las Vegas residents' are:
Some residents believe they should reduce water consumption
Other residents want to keep their swimming pools and be able to water their lawns
Why is Las Vegas so reliant on Lake Mead for water?
Las Vegas is so reliant on Lake Mead for its water supply because the water for Las Vegas used to come from natural springs.
Over-abstraction meant that these were drained completely by the 1960s.
Why are farmers in Nevada so concerned about the demand for water from Las Vegas?
The farmers in Nevada are concerned that water consumption by Las Vegas will reduce the amount of water available for irrigation.
Give two steps the government has taken to reduce water demand in Southern Nevada.
The government have taken several steps to reduce water use including:
In 2022 and 2023 they reduced the allocation of water to Southern Nevada
Bans on new golf courses
Restrictions on the amount of grass allowed in new developments
Support for businesses in reducing water use
Recycling of wastewater
Banning the use of sprinklers and hoses between 11am and 7pm
What is water conservation?
Water conservation is the practice of using water efficiently and responsibly to reduce unnecessary water consumption and waste.
Define the term groundwater management.
Groundwater management is the practice of monitoring and regulating the abstraction and recharge of groundwater from aquifers to ensure a sustainable balance between water withdrawal and replenishment.
What is meant by water recycling.
Water recycling, also known as water reclamation or wastewater reuse, is the process of treating and purifying wastewater from domestic, industrial, or agricultural sources for beneficial reuse.
True or False?
Installing water-efficient appliances, such as low-flush toilets and water-efficient washing machines, can help conserve water.
True.
Installing water-efficient appliances can significantly reduce water consumption and waste in households and contribute to sustainable water management.
Define drip irrigation.
Drip irrigation is an efficient irrigation method that delivers water directly to the roots of plants through a network of pipes, emitters, and tubing, minimizing water loss through evaporation or runoff.
Define the term aquifer recharge.
Aquifer recharge is the process of replenishing an aquifer with water from various sources, such as surface water, precipitation, or artificial injection, to maintain a sustainable groundwater supply.
True or False?
Water meters can encourage water conservation by making people aware of their water consumption and promoting responsible use.
True.
Water meters can encourage water conservation by making people aware of their water consumption and promoting responsible use, as they are charged based on their actual water usage.
What does water stress mean?
Water stress refers to a situation where the demand for water exceeds the available amount during a certain period or for an extended period, potentially leading to water shortages and adverse impacts on human health and the environment.
Define the term sustainable water management.
Sustainable water management is the practice of utilising and managing water resources in a way that meets the needs of the present without compromising the ability of future generations to meet their own needs while minimising negative impacts on the environment.
Define the term grey water.
Grey water is the term used to describe domestic wastewater such as from sinks, showers, baths, dishwashers and washing machines. It can be used where drinking quality water is not required.
Name the two water transfer projects in Spain.
The two water transfer projects in Spain are the Tagus-Segura project and the Ebro project.
What method is Spain using to ensure future water supply?
Spain has now moved to utilising desalinisation plants to meet the demand for water. Two additional plants are being built to open in 2028 and 2029. The estimated cost is €467 million.
What was the aim of the South-North Water Transfer project in China?
The aim of the South-North Water Transfer project was to transfer 12 trillion gallons of water a year from the south of China to the area around Beijing where the demand for water is greater than the supply.
Give three disadvantages of the South-North Water Transfer project?
There were several disadvantages of the South-North Water Transfer project including:
The cost - US$79 billion had been spent by 2014
Many people had to be relocated
In some areas in the south, water use had to be restricted to ensure there was enough to transfer
Droughts in the south mean less water is available