1. Water Resources

2. Water Cycle
Water is constantly moving among the oceans, the atmosphere, the solid Earth, and the biosphere.
r/kids/flash/flash_watercycle. html

3. Parts of the water cycle
Evaporation – water changes into vapor into the air
Precipitation – liquid or solid water from the clouds
Infiltration – water moving through the ground
Transpiration – water released from plants
Runoff – when flash rain storm hits the ground and is not absorbed.

4. What does Water Balance Mean?
Precipitation equals Evaporation

5. Water Facts of Life
There is the same amount of water on Earth as there was when the Earth was formed. The water from your faucet could contain molecules that dinosaurs drank.
75% of the human brain is water and 75% of a living tree is water.
A person can live about a month without food, but only about a week without water.
The average total home water use for each person in the U.S. is about 50 gallons a day.
Water expands by 9% when it freezes. Frozen water (ice) is lighter than water, which is why ice floats in water.

6. Water Supply in the World

7. Distribution of the Water on Earth
71% of Earth is water
97% in the oceans
3% is freshwater
2% in ice and glaciers
0.6% in underground water
0.4% in rivers, streams, lakes and atmosphere

8. Water Supply & Use

9. How is water used? 70% - Irrigation 20% - Industry
10% - Cities & Residence

10. Oceans currents

11. Ocean circulation also influences climate
Ocean circulation: ocean water exchanges heat in the water with the atmosphere
Thermohaline circulation: a worldwide current system in the ocean.
Warmer, fresher water moves along the surface and carries heat to Europe
North American Deep Water (NADW): the deep portion of the thermohaline circulation
denser, saltier, cool water that sinks
moves deep beneath the surface

12. NADW is vulnerable
If Greenland’s ice melts, freshwater runoff would dilute surface waters, making them less dense, and stopping NADW. – This has occurred in the past

13. Ocean Currents 1. Primary Forces--start the water moving
Solar Heating
Winds
Gravity
Coriolis
2. Secondary Forces--influence where the currents flow

14. Warm and Cold Currents
Warm ocean currents: warm water from tropics to poles.
Cold ocean currents: cold water poles toward the equator.
The Gulf Stream, is a warm-water current that moves up the Eastern coast of the United States