Water resources: reliable supply and competing uses
Separate rainfall from accessible water, compare transfer and treatment, and evaluate conservation.
Explain water insecurity
Water security depends on amount, timing, quality, access and reliability. Rainfall can be plentiful while usable supply is limited by pollution, storage or infrastructure.
Demand includes households, farming and industry. Withdrawals differ from consumption because some water returns to the system, often with changed quality or timing.
Worked example
A fictional reservoir stores 40 million m³ and supplies 2 million m³ weekly. Dividing gives 20 weeks only if there are no inflows, evaporation, reserve requirements or demand changes.
Common mistake: Storage divided by demand is a simplified duration, not a secure forecast.
Compare supply strategies
Storage, transfers, treatment, reuse and desalination affect different sources and locations. Energy, waste streams and upstream/downstream impacts need evaluation.
Singapore’s supply approach provides bounded evidence for reuse and diversification. It does not satisfy every board’s requirement for a local LIC/NEE scheme.
Worked example
A fictional transfer takes 10 units from an upstream flow of 50. The remaining 40 represents a 20% reduction at that point before return flows and other changes.
Common mistake: Water supplied to one place can change availability elsewhere.
Judge demand management
Metering, leakage reduction, efficient devices and restrictions can reduce different forms of demand. Effects depend on user behaviour, cost and implementation.
Cape Town’s drought evidence prompts questions about collective response and unequal capacity to cope. Reduced demand needs to be measured over a defined period.
Worked example
Fictional daily demand falls from 200 to 150 units: 25%. If the population also changes, compare per-person values as well as totals.
Common mistake: A lower total need not mean every household reduced consumption equally.
Try a different resource
GIS site selection
This training rule requires at least 2 hectares, outside protected land and the indicated flood zone. Among eligible sites, choose the lowest stated walk time. It is an explicit exercise rule, not a real planning approval.
Scroll the diagram sideways to see the full resource.
| Site | Protected land | Flood zone | Area (hectares) | Walk to bus stop (min) |
|---|---|---|---|---|
| A | No | No | 3 | 11 |
| B | No | Yes | 2 | 19 |
| C | Yes | No | 5 | 15 |
| D | No | No | 5 | 7 |
Resource description
North is up. Blue band: excluded flood zone. Green block: protected land. Sites: A: protected no, flood zone no, area 3 hectares, walk 11 minutes; B: protected no, flood zone yes, area 2 hectares, walk 19 minutes; C: protected yes, flood zone no, area 5 hectares, walk 15 minutes; D: protected no, flood zone no, area 5 hectares, walk 7 minutes. Minimum area 2 hectares.
Write an explanation
Check your answer
- Explain a mechanism for each approach.
- Trace users and locations affected.
- Evaluate reliability, energy and ecological effects.
- Keep case scope and option requirements visible.
Practise and review a written answer
Case studies
Singapore’s diversified water supply · Cape Town’s water-security crisis · The shrinking Aral Sea
These pages provide selected evidence. Check the whole case requirement with your teacher.
Read further
- water.usgs.gov — source or course reference
- www.aqa.org.uk — source or course reference
- www.aqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.sqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.eduqas.co.uk — source or course reference
- www.eduqas.co.uk — source or course reference
Water security and competing uses · Adaptation to changing conditions
Course links
AQA GCSE Geography · Higher Geography · Pearson Edexcel GCSE Geography A · Eduqas GCSE Geography A · Eduqas GCSE Geography B
Next topics
Food security: supply, access and sustainable choices · Water cycles: budgets, residence time and feedback
Selected teaching sequence with fictional worked data. The linked case records supply bounded evidence; they do not satisfy every course case requirement.
Scottish links identify reusable parts of the topic. Scottish landforms, soil, weather and disease requirements need additional course-specific teaching.