Water supply & demand (WJEC Eduqas GCSE Geography B): Revision Note

Specification link

This page covers section 3.3.1 of the WJEC Eduqas GCSE specification.

3.3.1 - Why does supply and demand for water vary over time and space?

• An overview of past and present global trends in water supply and demand.

• The concepts of water footprints and water security.

• The social, economic and environmental reasons why supply and demand for water varies over time and place.

• The links between population change, economic growth, consumerism and increasing demands for water.

Past and present trends in water supply and demand

Water supply

• Only 2.5% of the water on Earth is freshwater

• Approximately 68.7% of freshwater is stored in glaciers and ice sheets, and 30% is groundwater

• The remaining 1.3% of freshwater is in rivers, soil moisture, lakes and the atmosphere

  • This is not evenly distributed across the globe—Canada contains more lakes than the rest of the world combined

• The supply of water humans use comes from three main sources:

  • Lakes and rivers

  • Aquifers

  • Ice and glaciers

• The amount in each of these stores depends on the climate

  • In Peru, over 20 million people rely on water supply from glacier ice melt

  • Brazil's water supply is mainly from lakes and rivers

  • Over 60% of India's water comes from groundwater

Global demand for water

• The global demand for water is increasing

• Between 1934 and 2014, demand increased from 1 trillion m³ to 4 trillion m³

Water security

• To be water secure is to have a clean, reliable source of water 

• A place or country that does not have this is water insecure

Why is water security important?

• Populations need access to safe, sufficient and affordable water

• This is required to meet basic needs for:

  • Drinking

  • Sanitation and hygiene

  • Cooking

  • Well-being

• Adequate water supply is also needed for:

  • Industry

  • Food production

  • Energy production

  • Transport

  • Tourism

Water footprint

• Everyone has a water footprint

  • This is a measure of the amount of water each individual uses and their impact on water resources

• People use water every day for drinking, washing, cooking and sanitation

  • Every product used by people also uses water in its production and transport. This is called embedded water

  • On average, people use between 2,000 and 5,000 litres a day of embedded water

  • It takes:

    • Over 15,500 litres of water are required to make 1kg of beef

    • Making one cup of coffee takes 140 litres of water

    • To make 1kg of chocolate requires 24,000 litres of water

  • This is because water is used to water the crop or for the livestock, as well as during transport and other steps of production

Reasons for variation in water supply and demand

Social reasons for changing supply and demand

• Population growth - the more people there are, the more water is needed

• Many people in LICs do not have access to piped water and, as a result, are more cautious with water use

  • Water use also varies between regions in the same country

    • The demand for water is higher in urban areas than in rural areas

• Increased use of water in leisure and tourism - water parks, golf courses

Economic reasons for changing supply and demand

• Improving living standards - people have more appliances/sanitation, which use water

• Increased urbanisation 

• Increasing industry - water is needed for the production of goods and energy production

• Increasing use in commercial agriculture - more water is needed for livestock and crops

Environmental reasons for changing supply and demand

• Changing weather patterns due to climate change, including more extreme weather events and higher temperatures

  • This can lead to more frequent and severe droughts, which in turn affect the water supply.

• Industrial and agricultural waste can pollute surface and groundwater sources, making water unusable without costly purification

• The over-abstraction of water from rivers and aquifers can lower water tables and reduce the long-term sustainability of water sources. 

Links between factors affecting the supply and demand of water

• Population increase and economic growth lead to consumerism

  • This increases the water demand

• Water demand is greatest in HICs due to higher levels of domestic and industrial use

• The largest use of water in HICs tends to be in industry

• Unlike HICs, water use in LICs is mostly used for agriculture

  • Many people are still dependent on agriculture