Water Uses, Demand & Supply (Edexcel IGCSE Geography)

Water Uses

Spec point — 4GE1-S3.042

• 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 availability

• 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

*Water Use *

• 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

Spec point — 4GE1-S3.042

• 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

Global water use

Reasons for increased water demand

• There are several reasons for the global increase in water use:

  • 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

Exam Hint Remember when interpreting graphs you need to

• Identify the overall trend - is it increasing/decreasing/fluctuating
• Identify the highest and lowest points
• In any answer based on a graph make sure that you include figures

Areas of Water Shortages & Surpluses

Spec point — 4GE1-S3.042

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

Water surplus and deficit

• 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

Exam Hint Remember when interpreting maps you need to pay close attention to the key and title.

In the above example, the map shows both the surplus and deficit of water supply on a sliding scale. Areas of greatest water surplus are dark blue and areas of greatest water deficit are dark orange.