Water (AQA GCSE Geography): Revision Note

Global distribution of water

• Water is essential for life but only 2.5% of water on Earth is freshwater

Sources of water

• It is used in all aspects of life for domestic use, agriculture, industry and energy

• Global water use by sector is: 

  • 70% agriculture: irrigation of crops and water for livestock

  • 20% industry: producing goods and generating energy

  • 10% domestic: toilets, cooking, cleaning, washing

• The use by sector varies across countries depending on whether they are High Income Country (HIC), Newly Emerging Economy (NEE) or Low Income Country (LIC)

• Water supplies are not evenly distributed across the globe

Factors affecting supply 

• Climate

  • The amount of precipitation, rates of evapotranspiration and changes in climate affects the water available

• Geology

  • Affects where aquifers and groundwater are located and how much water is stored

• Rivers

  • Where they flow affects the availability of water

• Pollution

  • Approximately, 80% of waste water is untreated this impacts on the water quality and whether it is safe to use

• Over-abstraction:

  • Reduces the available stores of water

• Infrastructure

  • Pipes and canals used to transfer water, water treatment works and pumping stations are all expensive

  • Many LICs lack infrastructure particularly in rural areas due to the cost

  • Even in HICs and NEEs remote and rural areas may not have the infrastructure needed to supply water

• Poverty

  • Lack of money means that people cannot afford a clean water supply or bottled water

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

Water surplus

• Areas of water surplus (where the supply of water is greater than the demand) may be the result of:

  • High supply

    • High levels of 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 north USA

    • Russia

Water deficit

• Areas of water deficit (where the demand for water is greater than the supply) may be the result of:

  • Low supply

    • Lack of precipitation

    • High levels of evaporation

    • Poor water management

  • High demand

    • Increasing population

    • Industry

    • 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

• There are different levels of water shortage

• These are water stress and water scarcity:

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

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

Reasons for increasing water consumption

• Water consumption is increasing across the world

Global freshwater use

• Population growth

  • There are now over 8 billion people 

    • Each person requires about 2 litres of clean drinking water a day to remain in good health

    • In addition 18 litres per person is needed for things like sanitation and cooking

  • As well as an increase in domestic water demand, population growth also increases the use of water for:

    • Energy production

    • Agriculture

    • Industry

• Economic development

  • As countries develop the demand for water increases because:

    • People have more items which use water such as dishwashers, toilets and showers

    • Industry increases and factories use large quantities of water

    • Intensive agriculture is needed as people eat more food, and irrigation systems use large quantities of water

    • As more people move to urban areas the demand for water for drinking and sanitation increases

Impacts of water insecurity

• Water insecurity has the greatest impact on LICs and NEEs

• Lack of water treatment, infrastructure and waste disposal means that water supplies are:

  • Polluted by industrial waste

    • Where there are laws about waste disposal these are often not enforced

  • Agricultural pollution due to increasing use of pesticides and fertilisers

  • Domestic waste and sewage often get into the water supply

• Approximately 2.2 billion people lack access to safely managed water and 4.2 million lack safely managed sanitation

Health impacts

• This leads to:

  • Spread of waterborne diseases such as cholera, typhoid fever and dysentery

    • Diarrhoea (one of the most common effects of waterborne disease) which leads to the death of more than 0.5 million children a year

  • Unsafe water leads to 1.2 million deaths a year

  • Fall in income as people are unable to work due to illness

Death Rate per 100,000 people due to unsafe water sources

Agriculture

• In areas of water insecurity, irrigation will have to be reduced or may not be possible leading to:

  • A reduction in yields

  • Crop failure

  • Food shortages

  • Food price increases

Industry

• Industries use large quantities of water when this is not available this leads to:

  • A decrease in production

  • Loss of income for businesses and countries 

  • Interruption of energy supplies as electricity production may also rely on water supplies for cooling or hydroelectric power

Conflict

• At least 60% of the world's water sources (rivers and aquifers), cross a boundary between countries

  • The actions in one country can have significant impacts on countries and regions downstream, including:

    • Over-abstraction

    • Construction of dams and reservoirs

    • Pollution (sewage, industrial and agricultural waste)

  • Mismanagement of water sources can cause conflict between neighbouring countries and regions

• The construction of the dams on the Tigris and Euphrates rivers in Türkiye has significantly affected water flow into Syria and Iraq

  • During the filling of the Ilisu Dam in Türkiye in 2019 the water flow into Iraq decreased 50%

  • The quality of the water was also affected

    • In Basra people's health was severely affected with an increase in rashes, diarrhoea and vomiting

• On the border between India and China there have been clashes between communities due to concerns that China was reducing water flow into India

Strategies to increase water supply

• Increasing demand requires increasing water supply which can be achieved in a range of ways

  • Increased storage and diversion of supplies

  • Dams and reservoirs

  • Desalination

  • Water transfer

Water diversion and storage

• Example: Arizona in south west USA stores 600 million m³ water underground

Dams and reservoirs

• Examples: Three Gorges Dam in China; Ilisu Dam in Türkiye

Desalination

• Examples: Alicante II Seawater plant in Spain; Tampa Bay Water plant, USA 

Water transfer

• Examples: Wales to England, UK; South North Water Transfer project, China; Tegus-Segura, Spain

Example case study: South north water transfer project, China

River management in China

• The average precipitation in north-east China is approximately 200-400mm a year

• Most precipitation occurs during the brief wet season

• Average rainfall has steadily decreased since the 1950s

• The main industrial areas and regions of economic growth are on the North China Plain around Tianjin and Beijing

• The main water source for the area has been groundwater:

  • Demand for water in Beijing alone is 3.6 billion cubic meters 

  • Supply of freshwater in Beijing is 3 billion cubic meters

  • There is a significant water deficit

  • The over abstraction of groundwater has led to subsidence in some areas of the city of 11cm

South-north water transfer project

• Aims to transfer 12 trillion gallons of water a year from the south of China to the area around Beijing

• Central section was completed in 2014

• Final completion estimated to be in 2050

• It will link China's four main rivers: Yangtze, Yellow, Huaihe and Haihe

Advantages and disadvantages of the south-north water transfer project

Three Gorges Dam

• Constructed between 1994 and 2012

Advantages and disadvantages of the Three Gorges Dam

Sustainable water supply

• Sustainable water supplies:

  • Do not cause harm to the natural environment

  • Benefit local communities

  • Reduce waste

  • Can be used globally

Water conservation

• Involves reducing waste and using water less

  • Reduce leaks: it is estimated that globally 45 million m³ of water is lost per day through broken pipes and other leaks

  • Education: to inform people why water conservation is important encourage people to use and waste less 

  • Water meters: reduce water use as people pay for the water they use and so tend to waste less

  • Water efficient appliances: shower heads, low flush toilets and water efficient washing machines, dishwashers all use less water

  • Reduce pollution: pollution means that water cannot be used 

  • Efficient irrigation: drip irrigation reduces the amount of water lost through evaporation

Groundwater management

• Groundwater is the water stored underground in aquifers

• These can be affected by:

  • Over abstraction

  • Pollution

• Sustainable management of aquifers includes:

  • Maintaining a balance between water abstraction and recharge (either natural or artificial from rivers and lakes)

  • Monitoring water tables and quality

• In HICs groundwater is usually carefully monitored and managed

  • Although in some areas such as California there is increasing concern that over abstraction is resulting in the aquifers being severely depleted

• In LICs and some NEEs water pollution and over abstraction are common leading to exhaustion of aquifers in areas such as the Sahel in Sub Saharan Africa

Recycling

• Waste water from industry and domestic use which is treated so that it can be reused

Grey water

• Grey water is the term used to describe domestic waste water

• This can be used both inside and outside the home in any situation where drinking water quality is not required, including:

  • Flushing the toilet

  • Watering the garden

  • Cleaning car

Example case study: Shinja, Zimbabwe

Background

• The Shinja resettlement area suffers acute water shortages

• The community only had shallow wells 

• Which dry up a few months at the end of the rainy season

• This led to issues with sanitation and hygiene

Scheme

• Elephant pumps were installed in a number of communities

• The pumps are inexpensive to make and repair

• Made from local materials

• They are enclosed which reduces contamination

Impacts

• Water and sanitation diseases such as diarrhoea and bilharzia decreased

• Vegetable growing and livestock rearing increased

• Reduced the potential for conflict with neighbouring communities

• Time taken to collect water was significantly reduced

• Food intake increased and was of better quality

• Attendance at school increased as children were not involved in water collection