Water

• Water security


  The reliable availability of an acceptable quantity and quality of water for sustaining health, livelihoods and socio-economic development
• Global patterns of water surplus and deficit

  • Water surplus: when clean water supply exceeds demand, resulting in water security. This generally occurs in areas that have high rainfall and a low population density.
  • Water deficit: when demand for clean water exceeds supply, resulting in water insecurity. This generally occurs in areas that have low rainfall and a high population density.
• Water stress


  When the demand for clean water exceeds the amount available during a certain period or when poor quality restricts its use
• Reasons for rising global water demand

  • Economic development
  • Population growth
• Economic development


  • Industry and energy production put huge strains on the water supply. As people earn more money, living and hygiene standards improve, using more water.
• Population growth


  • An increasing number of people will need water for drinking, washing and domestic use. To feed the growing population, food production is increasing, using vast amounts of water.
• Factors affecting water availability

  • Climate
  • Pollution
  • Poverty
  • Geology
  • Over-abstraction
  • Limited infrastructure
• Climate


  • Areas with low precipitation are likely to suffer from water insecurity, especially if they are hot as lots of water is lost through evaporation. Climate change is also making the weather more unpredictable with many arid areas getting drier and hotter.
• Pollution


  • Pollution reduces the amount of clean water available for human use. It is a particular problem in industrial areas that rely on non-renewable energy and that generate high levels of waste.
• Poverty


  • In LICs and NEEs, many people cannot afford to pay water providers for clean water. Many people have no option but to get their water from communal wells and pipes or rivers.
• Geology


  • Water is unable to soak through hard, impermeable rock (e.g. granite). Instead, it flows over the rock surface into rivers, lakes, and reservoirs, which are easy to access. Conversely, water soaks into permeable rock (e.g. sandstone), sometimes forming underground stores called aquifers. These are not easy to access but can increase water availability in dry areas.
• Over-abstraction


  • Water can be abstracted from a source quicker than it can be replenished. This can lead to surface water and groundwater stores drying up.
• Limited infrastructure


  • Poor or lacking infrastructure can affect water availability, limiting supply and access. Even in the UK, almost 20% of the public water supply is lost each year through leakage.
• Impacts of water insecurity

  • Disease and pollution
  • Food production
  • Industrial output
  • Conflict
• Disease and pollution


  • When water is scarce, people may resort to drinking untreated or polluted water, which can give rise to waterborne diseases such as cholera. Chemicals from agriculture and manufacturing can also lead to poisoning.
• Food production


  • Irrigation is vital to commercial agriculture. An insufficient water supply can reduce crop yield and hinder livestock farming. The resulting drop in food production can lead to malnutrition and starvation.
• Industrial output


  • Industry relies heavily upon water for manufacturing, cooling and hydroelectric power. Water scarcity can lead to drops in production and dependence on expensive imports, greatly harming the economy.
• Conflict


  • Water insecurity can lead to conflict, especially where multiple countries share supplies. For example, a dam built by one country to improve its water supply could reduce the water supply of countries downstream.
• Strategies to increase water supply

  • Diverting supplies and increasing storage
  • Dams and reservoirs
  • Desalination
• Diverting supplies and increasing storage

  • Water can be diverted from areas of water surplus to areas of water deficit using water transfer schemes. Water can be stored in tanks, aquifers or reservoirs for use in times when there is a water deficit. However, water transfer is not without its drawbacks - it is very expensive and can disrupt ecosystems and kill wildlife.
• Dams and reservoirs


  • A dam is a barrier built across a river. It traps water behind it to form an artificial lake, or reservoir. Dams and reservoirs can be used to generate hydroelectric power (HEP). However, dams are expensive to construct and maintain. Reservoirs also flood agricultural land, disrupt ecosystems and reduce soil fertility downstream, creating conflict with farmers.
• Desalination


  • Desalination is the process of removing minerals from saltwater (e.g. from the sea or tidal rivers) to make it suitable for drinking or irrigation. Desalination is mostly used in wealthy Middle Eastern countries such as Saudi Arabia. However, it is an extremely expensive process that requires a huge amount of energy.
• Household water conservation


  • People can shower instead of bathing, reduce use of washing machines and other water-intensive appliances, and use more efficient appliances. Houses can also be fitted with water meters to discourage excessive water usage.
• National water conservation


  • The water infrastructure can be improved to reduce leaking. In agriculture, farmers can switch to more efficient forms of irrigation. Industry, as the biggest user and polluter of water, can be controlled to help conserve freshwater.
• Groundwater management


  • Groundwater stores, such as aquifers, are at risk from pollution and over-abstraction. Extraction can be monitored regularly to prevent over-abstraction, and governments can impose laws limiting the amount of groundwater extraction. Groundwater can also be artificially replenished or recharged.
• Water recycling


  • Once water has been used, it can be treated and used again, reducing the need to extract more water from natural resources. Recycled water can be used for irrigation, industry, flushing toilets and even washing. 'Grey' water, such as from washing machines and showers, can also be recycled without first being treated, for use in toilet flushing or watering gardens.