UPSC Prelims 2005 Q115: Environment & Ecology – Water & Wetland Conservation
Virtual water trade is being looked at by experts as a solution to the world’s water crisis.
What does virtual water (VW) imply?
- (a) Volume of heavy water required to replace ordinary water.
- (b) Volume of water required to produce a commodity or service.
- (c) Volume of water saved by using rainwater harvesting.
- (d) Volume of water utilized by an effective flood control.
Answer: (b) Volume of water required to produce a commodity or service.
Explanation
Virtual water
| Option | Meaning |
|---|---|
| Volume of water required to produce a commodity or service | Virtual water (embedded water) |
| Heavy water to replace ordinary water | Nuclear moderator, unrelated |
| Water saved by rainwater harvesting | Conservation, not virtual water |
| Water used in flood control | Not virtual water |
Virtual water is the total volume of water needed to produce a commodity or service; trading water-intensive goods moves this water between countries.
Answer: (b) Volume of water required to produce a commodity or service.
Why each option is right or wrong
- (a) Incorrect. Heavy water is deuterium oxide used in reactors.
- (b) CORRECT. Virtual water is the water embedded in producing a good or service.
- (c) Incorrect. Rainwater harvesting saves real, not virtual, water.
- (d) Incorrect. Flood control is not virtual water.
Key point
Virtual water: about 1000 litres per kg of wheat, far more for meat; coined by J. A. Allan.
Remember
Virtual water is the water embedded in producing goods and services.
Common mistakes
- Reading virtual as unreal water.
- Mixing it with heavy water in nuclear science.
- Confusing it with the water footprint of a country.
Exam tip
Virtual water trade: water-rich countries export water-intensive crops.
Sources
- UNESCO-IHE — water footprint and virtual water
- J. A. Allan — "Virtual Water: A Strategic Resource, Global Solutions to Regional Deficits", Ground Water, vol. 36 (1998)