Evaluate water-management strategies
Compare water-demand, supply and infrastructure strategies using effectiveness, equity, cost and ecosystem evidence.
Exam scope and assessment notes
Original StudyForA teaching and practice, not Cambridge-authored questions, mark schemes or official grades. Cambridge expects candidates to study all eight topics, carry out investigative work and learn teacher-selected case studies. This course does not replace a centre's named case-study examples, current local environmental data, supervised fieldwork or the candidate's own investigation. Practice datasets are illustrative, not observations from a real place. No official assessment or certification is provided. The examples and practice datasets in these lessons are fictional and formative; learners must add their centre's verified case studies and current local evidence.
Before you begin
- Cambridge recommends prior environmental/science study equivalent to IGCSE or O Level. This is an AS-only qualification; use the exam-year syllabus and confirm centre entry details.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What makes environmental evidence useful?
What you will learn
- Match a management strategy to a cause of water insecurity
- Evaluate reliability, cost, access and ecological effects
- Use dated regional evidence and identify affected groups
Match action to cause
Supply options in the syllabus include sustainable extraction, piped supply, aquifers and artesian wells, boreholes, gravity-fed schemes, reservoirs and dams. Demand options include improved irrigation, crops needing less water, recycling and rainwater catchment; education, poverty reduction, international aid or agreement and rationing are also possible.
Desalination uses energy and produces brine; dams can displace communities and alter rivers; groundwater withdrawal may exceed recharge; irrigation can cause salinisation; pricing can reduce waste but threaten affordability without protections. Match the action to the stated cause and compare reliability, access, cost and ecosystem effects.
Evaluate outcomes for different groups
A case study should connect strategy to the cause and show who gains or bears costs. Compare reliability, water quality, ecosystem change, energy, maintenance and access.
Use dated, sourced evidence. Teachers select the syllabus case-study region; this general framework does not replace the learner's named and current example.
Sources for this lesson
Pause and explain
What makes a water-management evaluation balanced?
Worked example
A dry coastal city considers desalination and leakage repair. Compare the options.
Show the worked solution
- Estimate water saved or added.
- Compare energy, cost, timing and distribution.
- Consider a combined plan and safeguards.
Answer Leak repair can reduce losses quickly but cannot meet rising demand if losses are already low. Desalination adds a weather-independent supply but costs energy, money and brine management. A combined plan should include efficiency, affordability and ecosystem monitoring.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A farm withdraws groundwater faster than recharge. Compare two strategies for long-term security.
Give me a hint
Address demand and source sustainability.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply match a management strategy to a cause of water insecurity to the stated context.
- Explain the inference and one limitation or trade-off.
Efficient irrigation and scheduling can lower withdrawals; crop choice or managed recharge may also help. Compare water levels, yields, costs and downstream users. Efficiency alone may not restore the aquifer if irrigated area expands.
Look for these in your work
- Match a management strategy to a cause of water insecurity
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
A dam supplies water but relocates a community and changes river flow. Outline a fair evaluation.
Give me a hint
Balance reliability with displacement and ecological flow.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply evaluate reliability, cost, access and ecological effects to the stated context.
- Explain the inference and one limitation or trade-off.
The dam may provide storage and drought resilience, but relocation can disrupt homes and livelihoods and altered flow affects habitats and downstream users. Compare alternatives, consult affected communities, assess compensation and monitor flow and water quality.
Look for these in your work
- Evaluate reliability, cost, access and ecological effects
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
Water use falls during a drought restriction. What shows whether the change lasted?
Give me a hint
Measure repeatedly after restrictions end.
Compare my reasoning
- Identify the relevant data, place or process in the prompt.
- Apply use dated regional evidence and identify affected groups to the stated context.
- Explain the inference and one limitation or trade-off.
Continue measuring household and sector use after restrictions end, alongside leakage, population and rainfall. Compare with a consistent baseline; a temporary drought response does not prove lasting demand reduction.
Look for these in your work
- Use dated regional evidence and identify affected groups
- Uses relevant evidence and explains the environmental mechanism
- Distinguishes observation, inference and limitation
Common mistakes
- Assuming new supply is always better than demand reduction
- Ignoring desalination energy and brine
- Evaluating strategy without identifying who receives water
What can you explain now?
What makes a water-management evaluation balanced?
Compare with the explanation
It compares reliability, access, cost, ecosystem effects and affected groups
The best option depends on the cause, place and users.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Why assess demand management and new supply together?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.