Water Supply and Consumption

This section explores water supply and consumption throughout the World. Water supply and consumption vary significantly across the world, creating water inequalities. Some regions have an abundance of water, while others experience severe shortages due to factors such as climate, population density, and economic development. Managing water resources effectively is essential for global sustainability.

Global Water Supply

Different regions of the world experience varying levels of water availability, influenced by climate, geography, and human activity.

• Equatorial Regions (e.g. the Amazon, Central Africa, Southeast Asia) receive high levels of rainfall due to warm, moist air rising. This ensures a plentiful water supply.
• Regions at around 30° latitude (e.g. Northern Africa, the Middle East, Central Australia) experience physical water scarcity due to low rainfall and high evaporation rates, making them arid and dry.
• Southern Hemisphere countries (e.g. Australia, Argentina, South Africa) have varied climates, with some areas experiencing water shortages, while others have high rainfall.
• Higher-latitude countries (e.g. Canada, Russia, Scandinavia) generally have sufficient water supplies due to regular precipitation and snowmelt.

Exceptions to this pattern exist in places where population density or economic challenges affect access to water, such as the UK (high population) or Nigeria (economic water scarcity).

Areas with Water Scarcity

• Northern Africa (e.g. Egypt, Libya, Algeria) and Central Asia (e.g. Uzbekistan, Kazakhstan) face extreme water shortages.
• The Sahel region (e.g. Chad, Niger, Sudan) suffers from high drought risk and low rainfall.

Reasons for Increasing Water Consumption

Water consumption has risen significantly due to two main factors:

Rising Population

• Water is essential for human survival—it makes up over 60% of the human body.
• A growing population means increased demand for drinking water, sanitation, and domestic uses.
• Global water supplies remain fixed, but demand continues to rise.

Economic Development

• As countries develop, their water use increases due to:
  • Modern appliances (dishwashers, washing machines, showers) consuming more water.
  • Commercial agriculture requiring large-scale irrigation.
  • Industrial processes using water in manufacturing and cooling systems.
  • Tourism growth, increasing water use in hotels, swimming pools, and attractions.
• HICs (High-Income Countries) have a higher water footprint than LICs (Low-Income Countries), as people in developed nations use more water per capita.

Case Study: Drought in California

Background

• Location: California, USA (west coast).
• Climate: The state has a diverse climate, with coastal areas experiencing rainfall, while eastern regions are desert-like.

Causes of the Drought

• Since 2011, California has experienced prolonged drought, worsened by:
  • Overuse of freshwater for irrigated farming (e.g. almond orchards use vast amounts of water).
  • Rising temperatures leading to higher evaporation rates.
  • Falling rainfall levels due to climate change and altered weather patterns.
  • Growing population increasing demand.

Impacts of the Drought

• Groundwater depletion:
  • Over-extraction led to falling water tables.
  • Subsidence (land sinking), damaging buildings and infrastructure.
  • Saltwater intrusion, contaminating underground water supplies.
• Wildfires: Dry vegetation increases wildfire risks, destroying homes and natural habitats.
• Agricultural losses: Reduced crop yields impacted farmers' incomes and food production.

Response

• No strict groundwater pumping limits were enforced until 2020.
• Residents were encouraged to reduce water consumption.
• Investment in water conservation and desalination projects.

Factors Affecting Water Availability

Several key factors influence global water supply and accessibility:

Climate

• Low rainfall and high temperatures lead to water deficits.
• High rainfall and cooler temperatures create water surpluses.

Geology

• Permeable rocks (e.g. limestone, chalk) allow water to flow underground, forming aquifers.
• Impermeable rocks (e.g. granite, clay) prevent water from soaking in, increasing surface water availability.

Pollution

• Untreated sewage and industrial waste contaminate water supplies.
• Groundwater pollution is a major issue, such as in South Africa, where gold mining has led to uranium and arsenic contamination.

Over-Abstraction

• Excessive water extraction from aquifers reduces supply.
• In Arizona’s Sonoran Desert, overuse of water for irrigation has caused land subsidence.

Poor Infrastructure

• Leaky or broken pipes waste water.
• In Kenya, water pumps have been fitted with transmitters to alert engineers when they break down.

Poverty

• Nearly 1 billion people in Africa lack access to clean water.
• This creates a cycle of poverty, where people become ill and cannot work, keeping them in economic hardship.

Impacts of Water Insecurity

Lack of Clean Water

• Women and girls in parts of Africa spend hours collecting water, limiting their education and employment opportunities.

Waterborne Diseases

• Dirty water spreads diseases such as:
  • Diarrhoea
  • Malaria (breeds in stagnant water)
  • Schistosomiasis (parasitic worms from contaminated water)

Reduced Food Production

• Irrigation increases crop yields by 400%, but water scarcity limits food availability.

Decline in Industrial Output

• Factories rely on water for production, cooling, and transport.
• Water shortages force businesses to reduce output, increasing reliance on expensive imports.

Water Conflicts

• Countries compete for control over rivers and reservoirs.
• Dams can be used politically, restricting water access to neighbouring nations.

Strategies to Increase Water Supply

Dams and Reservoirs

• Dams store large quantities of water, providing year-round supply.
• They also generate hydroelectric power (HEP) and help control flooding.
• Example: The Aswan Dam (Egypt) provides irrigation and electricity to millions.

Water Transfer Schemes

• Pipelines and canals move water from areas of surplus to areas of shortage.
• Example: China’s South-North Water Transfer Project transfers water from wet southern regions to dry northern cities.

Desalination Plants

• Remove salt from seawater to make it drinkable.
• Effective but expensive and energy-intensive.
• Example: The Thames Desalination Plant helps supply water to London during droughts.

Managing water sustainably is one of the biggest global challenges. With climate change, population growth, and increasing demand, countries must adopt conservation, infrastructure investment, and sustainable solutions to ensure a secure and fair water supply for future generations.