1. HYDROLOGIC CYCLE

2. CHEMICAL COMPOSITION OF WATER Water is made up of hydrogen (H 2 ) and oxygen (O 2 ). H + + OH - ↔ H 2 O

3. HYPOTHESIS: Water is an integral part of life that can be depleted if we use it faster than its replenished by nature.

4. AIM: To show water’s importance in everyday living and how we can sustain water over decades.

5. General Importance of Water. It is an essential medium for many biochemical reactions. Water transports nutrients, sediments and pollutants from the continents to the oceans via rivers, streams and surface runoffs.

6. Importance of Water to Human Health Sufficient water is needed in the body in order to keep the body hydrated. The brain needs water in order to function properly. Water provides the body with energy to do work.

8. How Humans Impact on the Hydrologic Cycle. Damming rivers slows water movement and increases evaporation. Watering agricultural fields depletes rivers, lakes, and streams and increases evaporation. Overdrawing surface and groundwater for domestic, agricultural, and industrial uses depletes groundwater. Clearing vegetation increases runoff and erosion while decreasing infiltration and transpiration. Emitting pollutants that dissolve in water changes precipitation.

9. SOLUTION Irrigate at night to reduce evaporation. Monitor soil moisture to add water only when necessary. Waste less water and subsidize water conservation. Use water meters. Fix water leaks. And much more.

10. References. Essential Environment: The Science Behind the Stories with “Mastering Environmental Science,” 2012, 4th edition. Authors: Withgott and Laposata. Publisher: Pearson.