Water management strategies
Big idea: There are many ways to increase water supply or reduce demand. The best approach depends on local conditions, available technology, and economic resources.
Increasing supply
- Dams and reservoirs — store water for dry periods (but displace communities, block fish migration)
- Desalination — removes salt from seawater (expensive, energy-intensive)
- Groundwater extraction — pumping from aquifers (risk of depletion, subsidence)
- Water transfer schemes — moving water between basins (expensive, environmental impacts)
- Rainwater harvesting — collecting precipitation (low-tech, local scale)
Reducing demand
- Drip irrigation — delivers water directly to plant roots (reduces waste by 30-70%)
- Water-efficient appliances — low-flow toilets, showerheads, washing machines
- Water pricing — higher prices encourage conservation
- Greywater recycling — reusing sink/shower water for gardens
- Public education — awareness campaigns reduce waste
- Fixing leaks — up to 30% of water lost in old infrastructure
When asked for management strategies, give a mix of supply-side and demand-side options. For each, add one quick drawback (cost, energy use, environmental impacts) to show evaluation.
IB-style question — evaluate desalination as a water strategy [4]
A coastal city is considering building a desalination plant to secure its water supply. Evaluate desalination as a strategy for sustainably managing water supply. [4]
How to answer it, step by step
- {"label":"**Give the advantages (max 2)**","body":"**Why it helps**<br>• Seawater supply is huge and rainfall-independent<br>• Produces safe drinking water → strong water security"}
- {"label":"**Give the disadvantages (max 2)**","body":"**Why it's limited**<br>• Very energy-intensive → high cost and emissions if fossil-fuelled<br>• Only works on coasts, and salty brine waste harms marine life"}
Final answer
Evaluate means BOTH sides — give pros AND cons; only one side caps you at 3 marks.