1. Where in the World is the Water?

2. The World’s Water Water is (almost) everywhere!
Yet, some say the world’s largest problem of today is a shortage of water!
The World Health Organization predicts that by mid-century, four billion of people —nearly 2/3 of the world’s present population—will face severe fresh water shortages.

3. The Blue Planet
Hydrosphere – the part of the Earth that contains water
Hydrologic Cycle - describes the continuous movement of water on, above, and below the surface of the Earth.

4. Distribution of Earth’s Water
2 categories of water in the Hydrosphere
Salt Water
Fresh Water
Both are based on the percentage of salinity
Salinity is the % of salt content

5. Distribution of Earth’s Water
71% of the Earth’s surface is covered with water.
Earth’s oceans contain 97% of the planet’s water (salt water).
3% is fresh water (low concentrations of salts).
Where is freshwater stored on Earth?
Do you think we can drink water from the ocean?
What is the main reason why ocean water is not potable (drinkable)?

6. Distribution of Earth’s Water
Salt water
Oceans
Freshwater
Frozen = 2/3
Liquid = 1/3 (accessible)

9. Frozen Water Most freshwater is frozen at the polar ice caps!!
Glaciers are masses of ice and snow that move slowly over the Earth’s surface.

10. Surface Water Sources include: Lakes Rivers Streams Reservoirs
The main uses of surface water include:
Drinking-water and other public uses
Irrigation uses
Industry and Hydroelectric Power

11. Lakes The Great Lakes are the largest freshwater system on earth.
They contain 84% of North America’s surface freshwater and 21% of the world’s surface fresh water supply. Only the polar ice caps contain more fresh water.

12. Watersheds
Watershed – a land area in which surface runoff drains into a river or a system of rivers and streams
What is your local watershed that supplies you with drinking water?

13. Colorado River and Water Wars
There is a longstanding treaty between US and Mexico over this river.
Serves over 30 million people.
About 45 dams along the river.

14. According to the USGS, about 77 percent of the freshwater used in the United States in 2005 came from surface-water sources. The other 23 percent came from groundwater.

15. Groundwater Sources include: Aquifers – a zone of material capable of
supplying ground water at
a useful rate from a well
porous rock
sediment with water in between (soil)
Water is attracted to the soil particles through the property of adhesion. With the property of both cohesion and adhesion, through capillary action, water is able to move from wet soil to dry areas.

16. The amount of water that is available to enter groundwater is influenced by:
local climate
slope of the land
type of rock found at the surface
vegetation cover
land use in the area
water retention, which is the amount of water that remains in the ground.
More water goes into the ground where there is a lot of rain, flat land, porous rock, exposed soil, and where water is not already filling the soil and rock.
The time water spends in a groundwater aquifer can be from minutes to thousands of years.
Groundwater is often called
“fossil water” because it has
remained in the ground for
so long, often since the end
of the ice ages.