Cambridge IGCSE Geography (0460): Theme 3.6 – Water – Study Guide

This guide covers Topic 3.6 Water from the Cambridge IGCSE Geography (0460) syllabus for examination in 2025 and 2026, Version 2 (published November 2022). Topic 3.6 sits in Theme 3, Economic development. It is examined in Paper 1 Geographical Themes (1 hour 45 minutes, 75 marks), where you answer three questions, one from each section. The syllabus says Paper 2 knowledge questions are also based on topics from the three themes, and it lists a water enquiry among its suggested topics for Component 3 Coursework.

Use this guide with the water revision notes and the water practice questions. For the whole course, go to the Cambridge IGCSE Geography hub and tick off topics on the IGCSE Geography checklist.

Coverage table

Syllabus reference	What you must know or be able to do (from the document)	Where assessed
3.6	Describe methods of water supply (including reservoirs/dams, wells and bore holes, desalination)	Paper 1; Paper 2 knowledge items
3.6	Describe the proportions of water used for agriculture, domestic and industrial purposes in countries at different levels of economic development	Paper 1; Paper 2 data items
3.6	Explain why there are water shortages in some areas	Paper 1
3.6	The impact of lack of access to clean water on local people and the potential for economic development	Paper 1
3.6	Demonstrate that careful management is required to ensure future supplies	Paper 1
3.6 case study	Water supply in a country or area	Paper 1
Enquiry	Suggested coursework topic: to what extent are problems of an uneven/unreliable water supply being solved by people and organisations in an area?	Component 3

The syllabus does not name a case study. Your teacher will confirm which country or area you use. You may use more than one.

Key terms

Term	Definition
Water supply	The provision of water to people, farms and industry from a source, through treatment and distribution
Reservoir	A lake, usually artificial, used to store water
Dam	A barrier built across a river to hold back water and create a reservoir
Well	A hole dug down to the water table to reach groundwater, usually shallow
Borehole	A narrow, deep shaft drilled by machine into an aquifer, with water raised by a pump
Aquifer	Rock that stores water and lets it pass through, such as sandstone or chalk
Water table	The upper level of saturated ground
Desalination	Removing salt from seawater or brackish water to make fresh water
Water stress	Demand for water is close to, or more than, the supply available
Physical water scarcity	There is not enough water to meet all demands
Economic water scarcity	Water exists but there is not enough investment in infrastructure or technology to supply it
Irrigation	Supplying water to crops artificially

1. Methods of water supply

The syllabus names three methods. Learn how each works, where it suits, and one strength and one problem.

Reservoirs and dams. A dam blocks a river valley. Water collects behind it in a reservoir, which stores wet-season rain for use in the dry season. Water is piped or sent down rivers and canals to towns and farms, and treated before people drink it. Large dams often also produce hydroelectric power and control floods.

• Strengths: store huge volumes; give a reliable supply through dry seasons; can serve several purposes.
• Problems: very expensive; flood farmland, homes and habitats; trap sediment; much water is lost by evaporation in hot climates.

Wells and boreholes. Both tap groundwater. A well is usually dug by hand and is shallow, so it can dry up when the water table falls. A borehole is drilled deeper by machine and lined, so it reaches more reliable water. Hand pumps or electric pumps raise the water.

• Strengths: cheap and local; groundwater is often cleaner than surface water; suit scattered rural villages far from piped supplies.
• Problems: if water is pumped out faster than rain refills the aquifer, the water table falls and wells dry up; shallow wells can be polluted by latrines or animal waste; pumps need maintenance.

Desalination. Seawater is turned into fresh water, usually by pushing it through very fine membranes (reverse osmosis) or by boiling it and collecting the steam (distillation).

• Strengths: an almost unlimited source for coastal places; does not depend on rainfall.
• Problems: uses a lot of energy, so it is costly and, if the energy comes from fossil fuels, adds greenhouse gases; leaves salty brine to dispose of; only practical near the coast.

Other methods you can mention beyond the named three include water transfer by pipeline or tunnel from a wetter area, rainwater harvesting from roofs, and recycling wastewater.

Example: Lesotho Highlands Water Project. Lesotho and South Africa developed this project together. Dams in the Lesotho mountains, including Katse Dam (185 m high; water deliveries began in 1998), store water, which is transferred into South Africa’s Vaal River system to supply the industrial Witwatersrand region. Lesotho receives royalties and hydroelectric power. In 2015 royalties were about 5% of Lesotho’s state income outside taxes. Critics point to people who lost their land and livelihoods, ecological impacts, and corruption cases linked to the project. A further dam, Polihali, is under construction.

2. How water use changes with development

The syllabus asks you to describe the proportions used for agriculture, domestic and industrial purposes in countries at different levels of development.

Globally, the FAO’s AQUASTAT database gives withdrawals as about 69% agricultural, 19% industrial and 12% municipal (domestic). The pattern changes with development:

Level of development	Typical pattern	Why
Low income	Agriculture is by far the largest use; industry is very small	Most people work in farming; irrigation is needed in dry seasons; few factories
Middle income (newly industrialising)	Agriculture still large, industry growing fast	Factories and power stations grow; cities expand
High income	Industry (including cooling power stations) often the largest share; domestic share higher	Many factories and power stations; high living standards mean showers, washing machines, gardens and swimming pools

Be careful with “proportion” and “amount”. A high-income country may use a smaller proportion for domestic purposes than for industry, yet each person still uses far more water at home than a person in a low-income country. Patterns also vary with climate, not just development, so use the data in the question rather than assuming.

Worked example (4 marks): “Using a pie chart of water use in a low-income country, explain why agriculture uses the largest proportion.”

The chart shows agriculture uses most of the country’s water, far more than industry or domestic use. This is because most of the population works in farming, so irrigation for crops such as rice takes large volumes, especially in the dry season when rainfall is low. There are few factories, so industrial demand is small. Domestic use is also low because many homes have no piped supply, so people use only what they can carry.

The answer quotes the resource, then gives three separate reasons, each linked to development.

3. Why there are water shortages in some areas

Learn shortages as two groups: not enough water, or not enough money and infrastructure to supply it.

Physical causes (supply is low or unreliable)

• Low annual rainfall, as in hot deserts.
• Seasonal or unreliable rainfall, so rivers and reservoirs dry out.
• High temperatures, so evaporation is high.
• Drought, which climate change may make more frequent in some regions.
• Few rivers or aquifers, or small land area to collect rain.

Human causes (demand is high or supply is damaged)

• Rapid population growth and urbanisation.
• Rising living standards, which raise use per person.
• Irrigation and industry taking large volumes.
• Over-abstraction of groundwater, lowering the water table.
• Pollution from sewage, farming and industry, which makes water unusable.
• Leaking pipes and poor maintenance.
• Lack of investment in dams, pipes and treatment: economic water scarcity.

Much of sub-Saharan Africa faces economic water scarcity, while arid regions such as North Africa and West Asia face physical scarcity.

4. The impact of lack of clean water

The syllabus names two impacts: on local people and on the potential for economic development.

Facts to use (WHO): in 2022, 2.2 billion people did not have safely managed drinking water, and 115 million people still collected untreated surface water from lakes, ponds, rivers and streams. WHO estimates that about 1 million people die each year from diarrhoea linked to unsafe water, sanitation and hand hygiene.

On local people

• Water-borne diseases such as cholera and diarrhoea, especially among young children.
• Hours lost walking to collect water, a task that often falls on women and girls.
• Children miss school, through illness or because they collect water.
• Poor hygiene and sanitation.

On economic development

• Sick workers produce less and families spend income on medical care.
• Time spent carrying water cannot be spent farming, trading or studying.
• Without a reliable supply, farms cannot irrigate and factories and tourism will not locate there.
• Lower school attendance limits skills, keeping incomes low.

This forms a cycle: poverty means no investment in water, and lack of water keeps people poor. WHO notes that better water supply can boost economic growth and reduce poverty. Link this to the development unit.

5. Careful management for future supplies

The syllabus asks you to demonstrate that management is needed. Show that demand is rising while supply is limited, then give strategies.

Strategy	Examples	Evaluation
Increase supply	New reservoirs, boreholes, desalination, water transfer, recycled wastewater	Costly; may harm environments; desalination is energy-hungry
Reduce demand	Metering and higher prices for heavy users; water-saving taps and toilets; public campaigns	Cheaper; pricing may hurt poorer households
Use water efficiently in farming	Drip irrigation, crops suited to dry climates, irrigating at night	Large savings because farming uses most water
Protect quality	Treat sewage, control farm and factory pollution	Keeps existing sources usable
Reduce losses	Repair leaking pipes	Saves water already treated
Small-scale solutions	Hand pumps, rainwater tanks, sand dams, run by communities	Cheap and locally run, but may fail without maintenance

Use phrases like “sustainable” and “future generations”, but always add a specific method.

6. Case study: water supply in Singapore

Singapore is a small, densely populated island city-state. It has heavy rainfall but little land to collect and store it. The government water agency, PUB, plans supply through “Four National Taps”.

1. Local catchment. About two-thirds of Singapore’s land is used as water catchment. Rain is collected through drains and canals into 17 reservoirs. Marina Barrage, opened in 2008, dammed the mouth of the Marina Channel to create a freshwater reservoir in the city centre.
2. Imported water. Under a 1962 agreement, which expires in 2061, Singapore can draw up to 250 million gallons a day from the Johor River in Malaysia.
3. NEWater. Treated used water is purified again by microfiltration, reverse osmosis and ultraviolet disinfection. NEWater was launched in 2002. PUB says it can meet up to 40% of Singapore’s current water needs. Most goes to industry, such as wafer fabrication plants, and air-conditioning cooling. In dry periods it is added to reservoirs.
4. Desalination. The first plant opened in 2005, and there are now five plants. Desalinated water does not depend on rainfall.

Managing demand. Total demand is about 430 million gallons a day. Prices include a water conservation tax, and households pay a higher rate above 40 cubic metres a month. Household use per person has fallen since 2003, when it was 165 litres a day. Only about 5% of water is lost as non-revenue water.

Evaluation

• Strengths: four sources reduce the risk from drought or from tension over imports; recycling and desalination do not depend on rainfall; leakage is very low.
• Limitations: NEWater and desalination use a lot of energy and are costly; the approach depends on high income and technology, so it transfers poorly to low-income countries; reliance on Malaysia continues until the agreement ends.

Worked example (7 marks): “For a named country or area, describe and explain how water is supplied.”

Singapore has heavy rainfall but little land to collect it, so it uses Four National Taps. First, about two-thirds of the island is catchment, and rain is channelled into 17 reservoirs, including Marina Reservoir behind Marina Barrage. Second, it imports water from Malaysia’s Johor River under a 1962 agreement lasting until 2061, because local catchment alone cannot meet demand of about 430 million gallons a day. Third, used water is purified into NEWater, which can meet up to 40% of current needs, mainly for industry. Finally, five desalination plants turn seawater into fresh water. Using several sources means supply is secure even in a drought, but the high energy cost is a weakness.

Notice: named place, numbers, a reason for each method, and a brief judgement.

Common errors

• Treating “well” and “borehole” as the same. A borehole is drilled deeper and reaches more reliable water.
• Writing that high-income countries use little domestic water because the share is small. Check proportion against amount.
• Saying “Africa has no water”. Distinguish physical and economic scarcity and name a place.
• Listing impacts of dirty water without linking to economic development when the question asks for it.
• Describing a case study with no figures or place names.
• Saying desalination solves shortages without its energy cost and brine problem.
• Writing “manage water better” without a specific method.

Where next

Revise rivers and drainage basins in the rivers guide and rainfall patterns in climate and natural vegetation. Water supply as a settlement site factor appears in population and settlement. Irrigation links to food production and factory location to industry. Hydroelectric power from dams is covered in energy, and water pollution in environmental risks of economic development. Then test yourself with the water practice questions.

Official syllabus

Cambridge IGCSE Geography (0460) syllabus for examination in 2025 and 2026, Version 2 (published November 2022), Topic 3.6 Water. Check your copy on the Cambridge International website, and ask your teacher which case study your centre uses.