Water Uses, Demand & Supply (Edexcel IGCSE Geography)

Water uses

• Only 2.5% of the water on Earth is freshwater

• Of this, 1.6% is stored in glaciers and ice sheets

• The remaining 0.9% of freshwater is in rivers, soil moisture, lakes and the atmosphere

• Global water use by sector is: 

  • 69% agriculture - irrigation of crops and water for livestock

  • 19% industry - producing goods and generating energy

  • 12% domestic - toilets, cooking, cleaning, washing

• The use of water by sector varies across countries depending on whether they are developed, emerging or developing

• In developing and emerging countries most water is used for agriculture

  • Areas with high average temperatures and low natural water supply have some of the highest levels of water use for agriculture

• The global use of water in leisure and tourism is increasing, particularly in developed countries

• In developed countries, most water is used for industry

Rising demand for & supply of water

• Demand is the amount of water required by users to meet their needs

• Supply is the amount of water available

• Water balance is the difference between supply and demand

• Countries may have a deficit (greater demand than supply) or surplus (more supply than demand)

• Water security is defined as the needs of the population being met by an acceptable quantity and quality of water

Water demand

• The global demand for water is increasing

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

Reasons for increased water demand

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

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

• increased urbanisation 

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

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

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

Water supply

• The supply of water comes from three main sources:

  • Lakes and rivers

  • Aquifers

  • Reservoir

• This supply of water is not evenly distributed

  • Many of the world's most populated areas are also the driest

• The World Health Organisation (WHO) estimates that 73% (2022) of the world's population have access to safely managed drinking water

Areas of water shortages & surpluses

Water Shortages (Deficit)

• Many areas of the world have water shortages (deficits)

• Water deficit can be due to:

  • Low supply - lack of precipitation, high levels of evaporation, poor water management

  • High demand - increasing population, industry and agriculture

  • A combination of low supply and high demand

• Areas with the greatest water deficit include:

  • Australia

  • North, East and South Africa

  • Middle East

  • West USA

  • Parts of South America 

  • India

• Many of these areas have a deficit due to low precipitation throughout the year 

• In some areas, demand is greater than supply due to increasing population, industry and agriculture

Water stress and water scarcity

• There are different levels of water shortage:

  • Water stress occurs when the supply of water is below 1700m³ a year per person

    • Over 2 billion (2021) people live in water-stressed countries

  • Water scarcity is when the supply is below 1000m³ a year per person

    • UNICEF estimates that 4 billion people (2024) experience water scarcity for at least one month of the year

Water surplus

• Some areas of the world have a water surplus 

• Water surplus can be due to:

  • High supply - high precipitation, low evaporation rates, effective water management

  • Low demand - low population, effective water management, low temperatures

  • A combination of high supply and low demand

• Areas with a surplus include:

  • North-east Brazil in the Amazon rainforest

  • Canada and parts of the northern USA

  • Russia