1. Ch. 13 Water Resources
Our liquid planet glows like a soft blue sapphire in the hard edged darkness of space. There is nothing else like it in the solar system. It is because of water.
John Todd

2. Case Study: The Colorado River Basin— An Overtapped Resource (1)
2,300 km through 7 U.S. states
14 Dams and reservoirs
Located in a desert area within the rain shadow of the Rocky Mountains
Water supplied mostly from snowmelt of the Rocky Mountains

3. Case Study: The Colorado River Basin— An Overtapped Resource (2)
Supplies water and electricity for about 30 million people
Las Vegas, Los Angeles, San Diego
Irrigation of crops that help feed America
Very little water reaches the Gulf of California
Southwest experiencing recent droughts

4. Aerial View of Glen Canyon Dam Across the Colorado River and Lake Powell
Figure 13.2: The Glen Canyon Dam across the Colorado River was completed in Lake Powell behind the dam is the second largest reservoir in the United States.
Fig. 13-2, p. 317

5. 13-1 Will We Have Enough Usable Water?
Concept 13-1A We are using available freshwater unsustainably by wasting it, polluting it, and charging too little for this irreplaceable natural resource.
Concept 13-1B One of every six people does not have sufficient access to clean water, and this situation will almost certainly get worse.

6. Freshwater Is an Irreplaceable Resource That We Are Managing Poorly
Access to water is
A global health issue
An economic issue
A women’s and children’s issue
A national and global security issue

7. Girl Carrying Well Water over Dried Out Earth during a Severe Drought in India
Figure 13.3: Many areas of the world suffer from severe and long-lasting shortages of freshwater. This has a major impact on the poor in some areas of India, especially women and children such as this young girl carrying water to her home in a very dry area. According to the United Nations, over 1.2 billion people—about 4 times the entire U.S. population—do not have access to clean water where they live. Each day girls and women in this group typically walk an average of almost 6 kilometers (4 miles) and spend an average of 3 hours collecting water from distant sources.
Fig. 13-3, p. 319

8. Most of the Earth’s Freshwater Is Not Available to Us
Freshwater availability: 0.024%
Groundwater, lakes, rivers, streams
Hydrologic cycle
Movement of water in the seas, land, and air
Driven by solar energy and gravity

9. Figure 3.16: Natural capital.
Condensation
Condensation
Ice and snow
Transpiration
from plants
Precipitation to land
Evaporation of
surface water
Evaporation
from ocean
Runoff
Lakes and
reservoirs
Precipitation to ocean
Runoff
Increased runoff on land covered with crops, buildings and pavement
Infiltration and percolation into aquifer
Increased runoff from cutting forests and filling wetlands
Runoff
Figure 3.16: Natural capital.
This diagram is a simplified model of the water cycle, or hydrologic cycle, in which water circulates in various physical forms within the biosphere. Major harmful impacts of human activities are shown by the red arrows and boxes. Question: What are three ways in which your lifestyle directly or indirectly affects the hydrologic cycle?
Groundwater in aquifers
Overpumping of aquifers
Water pollution
Runoff
Ocean
Natural process
Natural reservoir
Human impacts
Natural pathway
Pathway affected by human activities
Fig. 3-16, p. 67

10. Groundwater and Surface Water Are Critical Resources (1)
Zone of saturation
Spaces in soil are filled with water
Water table
Top of zone of saturation
Aquifers
Natural recharge
Lateral recharge

11. Groundwater and Surface Water Are Critical Resources (2)
Surface runoff
Watershed (drainage) basin

12. We Use Much of the World’s Reliable Runoff
2/3 of the surface runoff: lost by seasonal floods
1/3 is reliable runoff = usable
World-wide averages
Domestic: 10%
Agriculture: 70%
Industrial use: 20%

13. Science Focus: Water Footprints and Virtual Water (1)
Volume of water we directly and indirectly
Average American uses 260 liters per day
Flushing toilets, 27%
Washing clothes, 22%
Taking showers, 17%
Running faucets, 16%
Wasted from leaks, 14%
World’s poorest use 19 liters per day

14. Science Focus: Water Footprints and Virtual Water (2)
More water is used indirectly = virtual water
Hamburger, 2400 liters
Virtual water often exported/imported
Grains and other foods

16. Average Annual Precipitation and Major Rivers, Water-Deficit Regions in U.S.
More than enough renewable freshwater, unevenly distributed and polluted
Figure 13.4: The top map shows the average annual precipitation and major rivers in the continental United States. The bottom map shows water-deficit regions in the continental United States and their proximity to metropolitan areas having populations greater than 1 million (shaded areas). Question: Why do you think some areas with moderate precipitation still suffer from water shortages? (Data from U.S. Water Resources Council and U.S. Geological Survey)
Fig. 13-4, p. 322

17. Water Hotspots in 17 Western U.S. States
Figure 13.5: This map shows water scarcity hotspots in 17 western states that, by 2025, could face intense conflicts over scarce water needed for urban growth, irrigation, recreation, and wildlife. Some analysts suggest that this is a map of places not to live in the foreseeable future. Question: Which, if any, of these areas are found in the Colorado River basin (Figure 13-1)? (Data from U.S. Department of the Interior)
Fig. 13-5, p. 322

18. Water Shortages Will Grow (1)
Dry climates
Drought
Too many people using a normal supply of water
Wasteful use of water

19. Water Shortages Will Grow (2)
China and urbanization
30% earth’s land area experiences severe drought
Will rise to 45% by 2059 from climate change
Potential conflicts/wars over water
Refugees from arid lands
Increased mortality

20. Natural Capital Degradation: Stress on the World’s Major River Basins
Figure 13.6: Natural capital degradation.
The world’s major river basins differ in their degree of water scarcity stress, the measurement of which is based on a comparison of the amount of water available with the amount used by humans (Concept 13-1B). Questions: If you live in a water-stressed area, what signs of stress have you noticed? In what ways, if any, has it affected your life? (Data from World Commission on Water Use in the 21st Century)
Fig. 13-6, p. 323