1. Water: A Limited Resource
Chapter 14
Water: A Limited Resource

2. The Importance of Water
shapes continents
moderates our climate
is essential for all living organisms

3. The Importance of Water
Properties of Water
Composition and polarity
Hydrogen bonding properties

4. The Importance of Water
Properties of Water
Chemical composition of seawater

5. The Importance of Water
The Hydrologic Cycle

6. The Importance of Water
Our Supply of Fresh Water

7. The Importance of Water
Types of water:
surface water
runoff
drainage basin
groundwater
aquifers

8. The Importance of Water
Largest watersheds

9. The Importance of Water
Aquifers

10. Water Use and Resource Problems
Problems fall into 3 categories:
Too much
Too little
Poor quality / contamination (Chap. 22)

11. Water Use and Resource Problems
Too Much Water
Removing vegetation and constructing buildings increases flooding potential on flood plains

12. Water Use and Resource Problems
Too Much Water
Flood Management
Channelization

13. Water Use and Resource Problems
Too Much Water
Flood Management
Levees with natural river

14. Water Use and Resource Problems
Case-in-Point: The Floods of 1993

15. Water Use and Resource Problems
Too Little Water
Droughts
Overdrawing Surface Waters
Aquifer depletion
Causes subsidence
Can lead to saltwater intrusion

16. Water Use and Resource Problems
Saltwater intrusion

17. Water Use and Resource Problems
Too Little Water
Droughts
Overdrawing Surface Waters
Aquifer depletion
Causes subsidence
Can lead to saltwater intrusion
Salinization of Irrigated Soil

18. Average annual precipitation

19. Water Problems in the US
Surface Water
Most problems in the West and Southwest
Aqueducts transport water from distance sources

20. Water Problems in the US
Surface Water
Examples of problems:
Mono Lake
The Colorado River
Basin

21. Water Problems in the US
Groundwater
Aquifer depletion

22. Water Problems in the US
Groundwater
Aquifer depletion
- Ogallala Aquifer

23. Global Water Problems Water distribution globally is very inequitable
In addition, stable runoff varies
Drinking Water Problems
1.4 billion lack safe water
2.9 billion lack proper wastewater disposal

24. Global Water Problems Population Growth and Water Problems
India – 8,000 villages have no local water
China – water table falling 2-3 m / year
Pakistan – lack of water led to riots in 2001
Mexico – water table falling 3.5 m / year in Mexico City

25. Global Water Problems Sharing Water Resources among Countries
The Rhine River Basin

26. Global Water Problems Sharing Water Resources among Countries
The Aral Sea
1997
1976

27. Global Water Problems Sharing Water Resources among Countries
Potentially Volatile International Water Situations
Jordan River
Nile River

28. Water Management Providing a Sustainable Water Supply
Sustainable water use seeks to provide water to future generations without damaging ecosystems.

29. Water Management Providing a Sustainable Water Supply
Dams and Reservoirs
Pros –
Ensure year-round water supply
Hydropower
Recreation

30. Water Management Providing a Sustainable Water Supply
Dams and Reservoirs
Cons –
Alter ecosystems
Sediment Deposition

31. Water Management Providing a Sustainable Water Supply
Dams and Reservoirs
Example: Effect of dam on Colorado River in Grand Canyon

32. Water Management Providing a Sustainable Water Supply
Water Diversion Projects

33. Water Management Providing a Sustainable Water Supply Desalinization
Condenses
Two methods:
1) Distillation
Simplified process:
Salt water
Produces steam
Pure water is collected
Water boiled

34. Water Management Providing a Sustainable Water Supply Desalinization
Two methods:
1) Distillation
2) Reverse osmosis
Salt impermeable membrane
Salt water
Fresh water
Pressure
salt
H2O

35. Water Conservation Reducing Agricultural Water Waste
Drip or trickle irrigation

36. Water Conservation Reducing Agricultural Water Waste
Reducing Water Waste in Industry
Reducing Municipal Water Waste
Recycling water
Xeriscaping