1. Sources of Fresh Water
Chapter 10.3

2. When it rains, water… a) Evaporates  makes precipitation
b) Soaks into the ground
 called groundwater
c) Stays on the surface
 called run-off

3. Run-Off Run-off = water that stays on Earth’s surface
- Gravity pulls it downhill
 stream or river
 pond, lake or ocean

4. Run-off is important to think about
It brings good & bad things to lakes, rivers, & oceans with the water
Minerals
Nutrients
Pollution
These things affect plant and animal life

5. Run-off is important to think about

6. Factors that affect Run-off
1. Type of ground material
More run-off on rock
than soil

7. 2. Precipitation
Length of time
Amount

8. 3. Slope of the land
Steeper land
 less water absorbed
(more run-off)

10. 4. Vegetation

11. E.g., Clearcuts

12. Development (roads, cities)
Concrete doesn’t allow water to be absorbed into the ground

13. Run-off Problems Flooding Soil carried away by run-off Pollution
Soil & silt churned up  harmful to fish
Let’s think about this stuff!
Read p 376, 377, 378.
Do the Activity on p 378.
Make a drawing of the landscape, including the proposed development
“What to Do” #1
“What Did You Find Out?” #1 & 2

14. Drainage Basins
The area of land where precipitation falls and finds its way into a common river
Small streams feed into bigger streams which feed into rivers which feed into the ocean

15. Ground Water Water that is stored in pores of rocks underground
Aquifers are rocks
Layers with good
porosity
Water Table
Aquifer

16. Glaciers
2/3 of the world’s fresh water is trapped in glaciers

17. Large blocks of ice flowing downhill
Compressed snow becomes ice

18. Two Types Alpine – mountain glaciers
Continental – cover large areas of land: Antarctica and Greenland

19. Alpine glaciers move downhill until it is warm enough for them melt faster than gravity pulls it down Or
Glaciers reach the ocean and break off to form icebergs
Homework: Text p

20. Homework:
P (Textbook)