What you'll learn

• Why fresh water is unevenly distributed globally, nationally and locally.
• How water use differs between developed, emerging and developing countries.
• Why both the UK and lower-income countries can have water supply problems.
• How technology, stakeholders and sustainable management can reduce water shortages.

This is the Water option in Topic 6

In Edexcel GCSE Geography A Topic 6, you study either Energy or Water. These notes cover the Water resource management option.

1. The basics: what counts as fresh water?

Most water on Earth is salty ocean water. Only about 3% is fresh water, and most of that is locked up in ice sheets, glaciers or underground aquifers. A much smaller share is easily available in rivers, lakes and reservoirs.

Two important words run through this whole topic:

• Supply means the amount of water available for people, farming, industry and ecosystems.
• Demand means how much water people want or need to use.

2. Global freshwater distribution

Fresh water is unevenly distributed because of physical factors such as:

• Climate: areas with high rainfall, such as the Amazon Basin, usually have more water.
• Temperature: hot areas lose more water through evaporation, which is water changing from liquid to vapour.
• Relief: mountains can create high rainfall through uplift, especially on windward slopes.
• Geology: some rocks store water well as aquifers, which are underground stores of water.
• River systems: large drainage basins can move water from wetter areas to drier ones.

This sketch map shows the broad global pattern: surplus areas are often wet, less densely populated or have large river systems, while deficit areas often combine low rainfall with high demand.

Water availability varies at different scales

At a global scale, Canada, Russia, the Amazon Basin and the Congo Basin have large freshwater resources. North Africa, the Middle East, Central Asia and inland Australia face much greater pressure.

At a national scale, one country can contain both wet and dry regions. The UK is a good example: western and northern areas are wetter, while south-east England is drier but has high demand.

At a local scale, access can vary between neighbourhoods. A wealthy urban area may have piped treated water, while a nearby informal settlement may rely on standpipes, wells or untreated river water.

3. Water stress: comparing supply with demand

A useful way to think about relative water stress is:

$$Water\; stress=\frac{annual\; water\; withdrawals}{annual\; renewable\; freshwater\; supply}\times 100$$

If a country withdraws a large share of its renewable water each year, it is more vulnerable to drought, shortages and conflict between users.

4. How supply and demand have changed in the last 50 years

Over the past 50 years, global water demand has risen because of:

• Population growth: more people need water for drinking, cooking and washing.
• Urbanisation: cities need large, reliable water and sewage systems.
• Industrialisation: factories, energy production and manufacturing use water.
• Rising living standards: more appliances, showers, gardens and water-intensive diets.
• Irrigation: farming increasingly uses artificial watering to grow crops in dry areas.

Human intervention has also changed supply. Dams, reservoirs, canals, water transfers, desalination plants and wastewater recycling can increase usable supply in some places. However, over-abstraction of groundwater, pollution and climate change can reduce reliable supply.

Line graphs often show future population projections against available water resources. If the population line rises while available water stays roughly fixed, water available per person falls.

5. Water use in developed, emerging and developing countries

Water use is usually divided into three sectors:

Globally, agriculture uses the largest share of water — often quoted at around 70% of withdrawals — but the pattern varies by country.

In many developing countries, agriculture may dominate water use because economies rely heavily on farming and irrigation. Domestic use may be lower because fewer homes have piped water, washing machines, flush toilets or gardens.

In many developed countries, industry and domestic use often take a larger share because people have higher incomes, more appliances, more reliable piped supply and more water treatment. Agriculture may still be important, but it is often more efficient or less dominant in the economy.

6. Why the UK has water supply problems

The UK is not a dry country overall, but it still has water supply problems.

Uneven rainfall

The west and north of the UK receive more rainfall because moist air from the Atlantic rises over upland areas, creating relief rainfall. South-east England is drier but has high population density, London’s demand, intensive farming and many businesses.

Seasonal imbalance

Rainfall is often higher in winter, when demand is lower. Demand rises in summer because of gardens, tourism, farming and hot weather, but river levels and reservoirs may fall.

Ageing infrastructure

Much of the UK’s water and sewage network is old. Ageing pipes can leak, wasting treated water before it reaches users. Older combined sewer systems can also overflow during heavy rainfall, causing pollution in rivers and coastal waters.

7. Why emerging and developing countries have water supply problems

Many emerging and developing countries face water supply problems for different reasons.

Untreated water

Some communities rely on rivers, ponds, wells or standpipes without reliable treatment. This increases the risk of diseases such as cholera and diarrhoea.

Pollution of water courses

A water course is a channel such as a river or stream. Water courses can be polluted by untreated sewage, industrial waste, fertilisers, pesticides and dumped rubbish. Pollution reduces the amount of water that is safe to use.

Low annual rainfall

Some countries or regions, such as parts of the Sahel, the Horn of Africa and the Middle East, have low or unreliable rainfall. Drought can make shortages much worse, especially where storage is limited.

8. Stakeholders and attitudes to water use

Different stakeholders often disagree:

• Individuals may want cheap, reliable water for homes.
• Farmers may want irrigation to protect crops and income.
• Industries may want secure water supplies for production.
• Environmental organisations may want more water left in rivers and wetlands.
• Governments may prioritise economic growth, public health, food supply or international relations.

This creates conflict over exploitation, which means using a resource for human benefit. Exploitation can support development, but overuse can damage ecosystems and future supply.

9. Desalination: using technology to increase supply

Many modern plants use reverse osmosis, where seawater is pushed at high pressure through a membrane that allows water molecules through but blocks most salts.

This diagram shows how a reverse osmosis desalination plant turns seawater into usable fresh water, while producing salty waste called brine.

Desalination is useful for dry, coastal, wealthy places such as Saudi Arabia, the United Arab Emirates, Israel and Singapore. It provides reliable supply, but it is expensive, energy-intensive and can damage marine ecosystems if concentrated brine is returned carelessly to the sea.

10. Sustainable water management

Water needs sustainable management because:

• accessible fresh water is limited;
• demand is rising;
• pollution can make water unusable;
• climate change may increase droughts and floods;
• rivers, wetlands and wildlife need water too;
• shared rivers can create tension between countries.

Management happens at different scales:

• Local: fixing leaks, water meters, rainwater harvesting, community wells, sand dams.
• National: reservoirs, drought plans, water pricing, pollution laws, transfers between regions.
• International: treaties for shared rivers such as the Nile, Mekong or Colorado.

11. Located examples of sustainable management

Developed country: Singapore

Singapore is a developed city-state in South-east Asia. It has high demand, little land for large reservoirs and limited natural freshwater sources.

Singapore’s national water agency, PUB, manages water through the “Four National Taps”:

• local catchment water stored in reservoirs;
• imported water from Malaysia;
• NEWater, which is highly treated recycled wastewater;
• desalinated seawater.

It also uses water pricing, public education, efficient appliances and leakage control. This is relatively sustainable because it diversifies supply and reduces dependence on one source, although desalination still uses a lot of energy.

Emerging or developing country: Kenya

Kenya, in East Africa, has very uneven rainfall. Some areas, especially in the east and north, are semi-arid and vulnerable to drought. Rural communities may have limited piped water, while cities such as Nairobi have rapidly growing demand.

In counties such as Kitui and Makueni, communities and organisations have built sand dams across seasonal riverbeds. A concrete wall traps sand during floods, and water is stored in the sand behind the dam. People can then access water through shallow wells or pumps.

Sand dams are more sustainable than many high-cost schemes because they are local, low-energy and reduce evaporation. They can support farming, tree planting and time savings for households. However, they need suitable geology, community maintenance and enough seasonal rainfall to recharge.