1. Desalination Also called desalinization Removes salts from water
Two processes can be used
Distillation boils water out
Reverse osmosis filters water out

4. Water Use Humans use water for many functions
Drinking
Household and personal cleanliness
Industry
Agriculture
Largest use of water worldwide
Not all nations have equal access to water
National rates of water consumption vary widely

9. Agriculture – Furrow Irrigation
Oldest method of irrigation
Easy and inexpensive
Dig trenches in between rows of crops then fill trenches with water
35% of the water is lost to runoff or evaporation

10. Agriculture – Flood Irrigation
Covers an entire field with water and allows water to soak in
Can inhibit plant growth
20-30% of the water is lost to runoff or evaporation

11. Agriculture – Spray Irrigation
Sprays water over crops
Requires more equipment than flood or furrow irrigation
5-25% of the water is lost to evaporation or runoff

12. Agriculture – Drip Irrigation
Uses a drip hose to deliver water to a specific area
Hoses can be buried, which only lose 5% of the water to evaporation or runoff and prevents weeds
Best for perennial crops so hoses don’t have to be moved every year

13. Hydroponic Agriculture
Is growing crops in greenhouses with no soil and little pesticide
Uses a nutrient-rich water solution
Uses 95% less water than the most efficient irrigation techniques
Can produce more crops per hectare
Can be used all year

14. Industry Hydroelectric power Thermoelectric power Paper Metal refining
Uses 50% of all industrial water
Returns it to its source
Thermoelectric power
Used for cooling
Generates steam
Paper
Uses 125 L (33 gal) of water to make 1 kg
Metal refining

15. Water Ownership Is not easy to define
Water sources cross state and national boundaries
Different groups require different types of access
One proposed solution is to make water a free-market commodity
Read p !

16. Water Conservation Reduce use, recycle Dual-flush toilets
6 L flush for solid waste
3 L flush for liquid waste
Gray water recycling
Reuse water that is not drinkable for other activities that do not require drinkable water
Water-efficient manufacturing

17. Water Conservation Water-efficient manufacturing Xeriscaping
Reuse water for cooling or heating
Xeriscaping
Landscaping with drought-tolerant plants
Runoff and rain collection
Rain barrels collect water from hard surfaces