2. Water Resources
Chapter 13

3. Core Case Study: Water Conflicts in the Middle East: A Preview of the Future
Water shortages in the Middle East: hydrological poverty
Nile River
Jordan Basin
Tigris and Euphrates Rivers
Peacefully solving the problems

4. Three Major River Basins in the Middle East

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 (1)
Why is water so important?
Earth as a watery world: 71%
Freshwater availability: 0.024%
Poorly managed resource
Hydrologic cycle
Water pollution

7. Freshwater Is an Irreplaceable Resource That We Are Managing Poorly (2)
Access to water is
A global health issue
An economic issue
A women’s and children’s issue
A national and global security issue

8. Girl Carrying Well Water over Dried Out Earth during a Severe Drought in India

9. Most of the Earth’s Freshwater Is Not Available to Us
Hydrologic cycle
Movement of water in the seas, land, and air
Driven by solar energy and gravity
People divided into
Water haves
Water have-nots

10. We Get Freshwater from Groundwater and Surface Water (1)
Zone of saturation
Water table
Aquifers
Natural recharge
Lateral recharge

11. We Get Freshwater from Groundwater and Surface Water (2)
Surface runoff
Watershed (drainage) basin
Reliable runoff
1/3 of total

12. Natural Capital: Groundwater System: Unconfined and Confined Aquifer

13. Flowing artesian well Well requiring a pump Water table
Unconfined Aquifer Recharge Area
Evaporation and transpiration
Evaporation
Precipitation
Confined Recharge Area
Runoff
Flowing artesian well
Well requiring a pump
Stream
Figure 13.3
Natural capital: groundwater system. An unconfined aquifer is an aquifer with a permeable water table. A confined aquifer is bounded above and below by less permeable beds of rock, and its water is confined under pressure. Some aquifers are replenished by precipitation; others are not.
Water table
Infiltration
Lake
Infiltration
Unconfined aquifer
Less permeable material such as clay
Confined aquifer
Confining impermeable rock layer
Fig. 13-3, p. 316

14. We Use a Large and Growing Portion of the World’s Reliable Runoff
2/3 of the surface runoff: lost by seasonal floods
1/3 runoff usable
Domestic: 10%
Agriculture: 70%
Industrial use: 20%
Fred Pearce, author of When the Rivers Run Dry

15. Case Study: Freshwater Resources in the United States
More than enough renewable freshwater, unevenly distributed
Effect of
Floods
Pollution
Drought
2007: U.S. Geological Survey projection
Water hotspots

16. Average Annual Precipitation and Major Rivers, Water-Deficit Regions in U.S.

17. Figure 13.4
Average annual precipitation and major rivers (top) and water-deficit regions in the continental United States and their proximity to metropolitan areas having populations greater than 1 million (bottom). 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. 13-4a, p. 317

18. Average annual precipitation (centimeters)
Less than 41
81–122
41–81
More than 122
Figure 13.4
Average annual precipitation and major rivers (top) and water-deficit regions in the continental United States and their proximity to metropolitan areas having populations greater than 1 million (bottom). 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. 13-4a, p. 317

19. Figure 13.4
Average annual precipitation and major rivers (top) and water-deficit regions in the continental United States and their proximity to metropolitan areas having populations greater than 1 million (bottom). 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. 13-4b, p. 317

20. Metropolitan regions with population greater than 1 million
Figure 13.4
Average annual precipitation and major rivers (top) and water-deficit regions in the continental United States and their proximity to metropolitan areas having populations greater than 1 million (bottom). 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)
Acute shortage
Shortage
Adequate supply
Metropolitan regions with population greater than 1 million
Fig. 13-4b, p. 317

21. Water Hotspots in 17 Western U.S. States

22. Highly likely conflict potential
Washington
North Dakota
Montana
Oregon
Idaho
South Dakota
Wyoming
Nevada
Nebraska
Utah
Colorado
Kansas
California
Oklahoma
New Mexico
Arizona
Figure 13.5
Water 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 during the next 25 years. Question: If you live in one of these hotspot areas, have you noticed any signs of conflict over water supplies? (Data from U.S. Department of the Interior)
Texas
Highly likely conflict potential
Substantial conflict potential
Moderate conflict potential
Unmet rural water needs
Fig. 13-5, p. 318

23. Water Shortages Will Grow (1)
Dry climate
Drought
Too many people using a normal supply of water

24. Water Shortages Will Grow (2)
Wasteful use of water
China and urbanization
Hydrological poverty

25. Natural Capital Degradation: Stress on the World’s Major River Basins

26. Asia Europe North America Africa South America Australia Stress High
Figure 13.6
Natural capital degradation: stress on the world’s major river basins, 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)
Stress
High
None
Fig. 13-6, p. 319

27. Long-Term Severe Drought Is Increasing
Causes
Extended period of below-normal rainfall
Diminished groundwater
Harmful environmental effects
Dries out soils
Reduces stream flows
Decreases tree growth and biomass
Lowers net primary productivity and crop yields
Shift in biomes

28. In Water-Short Areas Farmers and Cities Compete for Water Resources
2007: National Academy of Science study
Increased corn production in the U.S. to make ethanol as an alternative fuel
Decreasing water supplies
Aquifer depletion
Increase in pollution of streams and aquifers

29. Who Should Own and Manage Freshwater Resources? (1)
Most water resources
Owned by governments
Managed as publicly owned resources
Veolia and Suez: French companies
Buy and manage water resources
Successful outcomes in many areas

30. Who Should Own and Manage Freshwater Resources? (2)
Bechtel Corporation
Poor water management in Bolivia
A subsidiary of Bechtel Corporation
Poor water management in Ecuador
Potential problems with full privatization of water resources
Financial incentive to sell water; not conserve it
Poor will still be left out

31. 13-2 Is Extracting Groundwater the Answer?
Concept Groundwater that is used to supply cities and grow food is being pumped from aquifers in some areas faster than it is renewed by precipitation.

32. Water Tables Fall When Groundwater Is Withdrawn Faster Than It Is Replenished
India, China, and the United States
Three largest grain producers
Overpumping aquifers for irrigation of crops
India and China
Small farmers drilling tubewells
Effect on water table
Saudi Arabia
Aquifer depletion and irrigation

33. Trade-Offs: Withdrawing Groundwater, Advantages and Disadvantages

34. Withdrawing Groundwater
TRADE-OFFS
Withdrawing Groundwater
Advantages
Disadvantages
Useful for drinking and irrigation
Aquifer depletion from overpumping
Sinking of land (subsidence) from overpumping
Available year-round
Aquifers polluted for decades or centuries
Exists almost everywhere
Saltwater intrusion into drinking water supplies near coastal areas
Renewable if not overpumped or contaminated
Figure 13.7
Advantages and disadvantages of withdrawing groundwater. Question: Which two advantages and which two disadvantages do you think are the most important? Why?
Reduced water flows into surface waters
No evaporation losses
Increased cost and contamination from deeper wells
Cheaper to extract than most surface waters
Fig. 13-7, p. 321

35. Natural Capital Degradation: Irrigation in Saudi Arabia Using an Aquifer

36. Case Study: Aquifer Depletion in the United States
Ogallala aquifer: largest known aquifer
Irrigates the Great Plains
Water table lowered more than 30m
Cost of high pumping has eliminated some of the farmers
Government subsidies to continue farming deplete the aquifer further
Biodiversity threatened in some areas
California Central Valley: serious water depletion

37. Natural Capital Degradation: Areas of Greatest Aquifer Depletion in the U.S.

38. Groundwater Overdrafts:
Figure 13.9
Natural capital degradation: areas of greatest aquifer depletion from groundwater overdraft in the continental United States, including the vast, central Ogallala aquifer. Aquifer depletion is also high in Hawaii and Puerto Rico (not shown on map). See an animation based on this figure at CengageNOW™. Question: If you live in the United States, how is your lifestyle affected directly or indirectly by water withdrawn from the essentially nonrenewable Ogallala aquifer? (Data from U.S. Water Resources Council and U.S. Geological Survey)
High
Moderate
Minor or none
Fig. 13-9, p. 322

39. Natural Capital Degradation: The Ogallala is the World’s Largest Known Aquifer

40. SOUTH DAKOTA WYOMING NEBRASKA COLORADO KANSAS OKLAHOMA NEW MEXICO
Figure 13.10
Natural capital degradation: The Ogallala is the world’s largest known aquifer. If the water in this aquifer were above ground, it could cover all of the lower 48 states with 0.5 meter (1.5 feet) of water. Water withdrawn from this aquifer is used to grow crops, raise cattle, and provide cities and industries with water. As a result, this aquifer, which is renewed very slowly, is being depleted, especially at its thin southern end in parts of Texas, New Mexico, Oklahoma, and Kansas. (Data from U.S. Geological Survey)
Miles
TEXAS
100
160
Kilometers
Saturated thickness of Ogallala Aquifer
Less than 61 meters (200 ft.)
61–183 meters (200–600 ft.)
More than 183 meters (600 ft.)
(as much as 370 meters or 1,200 ft. in places)
Fig , p. 323

41. Groundwater Overpumping Has Other Harmful Effects (1)
Limits future food production
Bigger gap between the rich and the poor
Land subsidence
Mexico City
Sinkholes

42. Groundwater Overpumping Has Other Harmful Effects (2)
Groundwater overdrafts near coastal regions
Contamination of the groundwater with saltwater
Undrinkable and unusable for irrigation

43. Solutions: Groundwater Depletion, Using Water More Sustainably

44. SOLUTIONS Groundwater Depletion Prevention Control Waste less water
Raise price of water to discourage waste
Subsidize water conservation
Tax water pumped from wells near surface waters
Figure 13.11
Ways to prevent or slow groundwater depletion by using water more sustainably. Question: Which two of these solutions do you think are the most important? Why?
Limit number of wells
Set and enforce minimum stream flow levels
Do not grow water-intensive crops in dry areas
Divert surface water in wet years to recharge aquifers
Fig , p. 324

45. Science Focus: Are Deep Aquifers the Answer?
Locate the deep aquifers; determine if they contain freshwater or saline water
Major concerns
Geological and ecological impact of pumping water from them
Flow beneath more than one country
Who has rights to it?

46. Active Figure: Threats to aquifers

47. 13-3 Is Building More Dams the Answer?
Concept 13-3 Building dam and reservoir systems has greatly increased water supplies in some areas, but it has disrupted ecosystems and displaced people.

48. Large Dams and Reservoirs Have Advantages and Disadvantages (1)
Main goals of a dam and reservoir system
Capture and store runoff
Release runoff as needed to control:
Floods
Generate electricity
Supply irrigation water
Recreation (reservoirs)

49. Large Dams and Reservoirs Have Advantages and Disadvantages (2)
Increase the reliable runoff available
Reduce flooding
Grow crops in arid regions

50. Large Dams and Reservoirs Have Advantages and Disadvantages (3)
Displaces people
Flooded regions
Impaired ecological services of rivers
Loss of plant and animal species
Fill up with sediment within 50 years

51. Advantages and Disadvantages of Large Dams and Reservoirs

52. The Ataturk Dam Project in Eastern Turkey

53. Some Rivers Are Running Dry and Some Lakes Are Shrinking
Dams disrupt the hydrologic cycle
Major rivers running dry part of the year
Colorado and Rio Grande, U.S.
Yangtze and Yellow, China
Indus, India
Danube, Europe
Nile River-Lake Victoria, Egypt
Lake Chad Africa: disappearing

54. 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

55. Case Study: The Colorado River Basin— An Overtapped Resource (2)
Supplies water and electricity for more than 25 million people
Irrigation of crops
Recreation

56. Case Study: The Colorado River Basin— An Overtapped Resource (3)
Four Major problems
Colorado River basin has very dry lands
Modest flow of water for its size
Legal pacts allocated more water for human use than it can supply
Amount of water flowing to the mouth of the river has dropped

57. Case Study: The Colorado River Basin— An Overtapped Resource (4)
What will happen if some of the reservoirs empty out?
Economic and ecological catastrophe
Political and legal battles over water

58. The Colorado River Basin

59. Aerial View of Glen Canyon Dam Across the Colorado River and Lake Powell

60. The Flow of the Colorado River Measured at Its Mouth Has Dropped Sharply

61. Hoover Dam completed (1935)30
Hoover Dam completed (1935) 25 20
Flow (billion cubic meters) 15
Glen Canyon Dam completed (1963) 10
Figure 13.16
The flow of the Colorado River measured at its mouth has dropped sharply since 1905 as a result of multiple dams, water withdrawals for agriculture and urban areas, and prolonged drought. (Data from U.S. Geological Survey) 5
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Year
Fig , p. 328

62. Case Study: China’s Three Gorges Dam (1)
World’s largest hydroelectric dam and reservoir
2 km long across the Yangtze River
Benefits
Electricity-producing potential is huge
Holds back the Yangtze River floodwaters
Allows cargo-carrying ships

63. Case Study: China’s Three Gorges Dam (2)
Harmful effects
Displaces about 5.4 million people
Built over a seismic fault
Significance?
Rotting plant and animal matter producing CH4
Worse than CO2 emissions
Will the Yangtze River become a sewer?