1. Water Resources
Chapter 13

2. 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

3. Three Major River Basins in the Middle East

4. 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.

5. 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

6. 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

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

8. 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

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

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

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

12. 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

13. 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

14. 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

15. 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

16. Water Hotspots in 17 Western U.S. States
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)

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

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

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

20. 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

21. 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

22. 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

23. 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

24. 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.

25. 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

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

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

28. 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

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

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

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

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

33. Solutions: Groundwater Depletion, Using Water More Sustainably

34. 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?

35. Active Figure: Threats to aquifers

36. 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.

37. 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)

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

39. 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

40. Advantages and Disadvantages of Large Dams and Reservoirs

41. The Ataturk Dam Project in Eastern Turkey

42. 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

43. 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

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

45. 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

46. 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

47. The Colorado River Basin

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

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

50. 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

51. 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?

52. 13-4 Is Transferring Water from One Place to Another the Answer?
Concept Transferring water from one place to another has greatly increased water supplies in some areas, but it has also disrupted ecosystems.

53. CA, U.S., Transfers Water from Water-Rich Areas to Water-Poor Areas
Water transferred by
Tunnels
Aqueducts
Underground pipes
May cause environmental problems
California Water Project

54. The California Water Project and the Central Arizona Project

55. Case Study: The Aral Sea Disaster (1)
Large-scale water transfers in dry central Asia
Salinity
Wetland destruction and wildlife
Fish extinctions and fishing

56. Case Study: The Aral Sea Disaster (2)
Wind-blown salt
Water pollution
Climatic changes
Restoration efforts

57. Natural Capital Degradation: The Aral Sea, Shrinking Freshwater Lake

58. 1976
2006
Figure 13.18
Natural capital degradation: the Aral Sea was once the world’s fourth largest freshwater lake. Since 1960, it has been shrinking and getting saltier because most of the water from the rivers that replenish it has been diverted to grow cotton and food crops (Concept 13-4). These satellite photos show the sea in 1976 and in It has split into two major parts, little Aral on the left and big Aral on the right. As the lake shrank, it left behind a salty desert, economic ruin, increasing health problems, and severe ecological disruption. Question: What do you think should be done to help prevent further shrinkage of the Aral Sea?
Stepped Art
Fig a, p. 331

59. Ship Stranded in Desert Formed by Shrinkage of the Aral Sea

60. China Plans a Massive Transfer of Water
South-North Water Transfer Project
Water from three rivers to supply 0.5 billion people
Completion in about 2050
Impact
Economic
Health
Environmental

61. 13-5 Is Converting Salty Seawater to Freshwater the Answer?
Concept We can convert salty ocean water to freshwater, but the cost is high, and the resulting salty brine must be disposed of without harming aquatic or terrestrial ecosystems.

62. Removing Salt from Seawater Seems Promising but Is Costly (1)
Desalination
Distillation
Reverse osmosis, microfiltration
15,000 plants in 125 countries
Saudi Arabia: highest number

63. Removing Salt from Seawater Seems Promising but Is Costly (2)
Problems
High cost and energy footprint
Keeps down algal growth and kills many marine organisms
Large quantity of brine wastes
Future economics

64. Science Focus: The Search for Improved Desalination Technology
Desalination on offshore ships
Solar or wind energy
Better membranes
Better disposal options for the brine waste
Reduce water needs, conserve water

65. 13-6 How Can We Use Water More Sustainably?
Concept We can use water more sustainably by cutting water waste, raising water prices, slowing population growth, and protecting aquifers, forests, and other ecosystems that store and release water.

66. Reducing Water Waste Has Many Benefits (1)
Water conservation
Improves irrigation efficiency
Improves collection efficiency
Uses less in homes and businesses

67. Reducing Water Waste Has Many Benefits (2)
Worldwide: 65–70% loss
Evaporation, leaks, etc.
Water prices: low cost to user
Government subsidies: more needed?

68. We Can Cut Water Waste in Irrigation
Flood irrigation
Wasteful
Center pivot, low pressure sprinkler
Low-energy, precision application sprinklers
Drip or trickle irrigation, microirrigation
Costly; less water waste

69. (efficiency 60% and 80% with surge valves)
Center pivot
(efficiency 80% with low-pressure sprinkler and 90–95% with LEPA sprinkler)
Water usually pumped from underground and sprayed from mobile boom with sprinklers.
Drip irrigation
(efficiency 90–95%)
Above- or below-ground pipes or tubes deliver water to individual plant roots.
Gravity flow
(efficiency 60% and 80% with surge valves)
Water usually comes from an aqueduct system or a nearby river.
Figure 13.20
Major irrigation systems. Because of high initial costs, center-pivot irrigation and drip irrigation are not widely used. The development of new, low-cost, drip-irrigation systems may change this situation.
Stepped Art
Fig , p. 335

70. Solutions: Reducing Irrigation Water Waste

71. Developing Countries Use Low-Tech Methods for Irrigation
Human-powered treadle pumps
Harvest and store rainwater
Create a canopy over crops: reduces evaporation
Fog-catcher nets

72. We Can Cut Water Waste in Industry and Homes
Recycle water in industry
Fix leaks in the plumbing systems
Use water-thrifty landscaping: xeriscaping
Use gray water
Pay-as-you-go water use

73. Solutions: Reducing Water Waste

74. We Can Use Less Water to Remove Wastes
Can we mimic how nature deals with waste?
Waterless composting toilets

75. We Need to Use Water More Sustainably
“The frog does not drink up the pond in which it lives”
Blue revolution

76. Solutions: Sustainable Water Use

77. What Can You Do? Water Use and Waste

78. 13-7 How Can We Reduce the Threat of Flooding?
Concept We can lessen the threat of flooding by protecting more wetlands and natural vegetation in watersheds and by not building in areas subject to frequent flooding.

79. Some Areas Get Too Much Water from Flooding (1)
Flood plains
Highly productive wetlands
Provide natural flood and erosion control
Maintain high water quality
Recharge groundwater
Benefits of floodplains
Fertile soils
Nearby rivers for use and recreation
Flatlands for urbanization and farming

80. Some Areas Get Too Much Water from Flooding (2)
Dangers of floodplains and floods
Deadly and destructive
Human activities worsen floods
Failing dams and water diversion
Hurricane Katrina and the Gulf Coast
Removal of coastal wetlands

81. Natural Capital Degradation: Hillside Before and After Deforestation

82. Forested Hillside After Deforestation Oxygen released by vegetation
Diverse ecological habitat
Evapotranspiration
Trees reduce soil erosion from heavy rain and wind
Tree roots stabilize soil
Vegetation releases water slowly and reduces flooding
Forested Hillside
Agricultural land
Stepped Art
Tree plantation
Roads destabilize hillsides
Overgrazing accelerates soil erosion by water and wind
Winds remove fragile topsoil
Agricultural land is flooded and silted up
Gullies and landslides
Heavy rain erodes topsoil
Silt from erosion fills rivers and reservoirs
Rapid runoff causes flooding
After Deforestation
Evapotranspiration decreases
Figure 13.25
Natural capital degradation: hillside before and after deforestation. Once a hillside has been deforested for timber, fuelwood, livestock grazing, or unsustainable farming, water from precipitation rushes down the denuded slopes, erodes precious topsoil, and can increase flooding and pollution in local streams. Such deforestation can also increase landslides and mudflows. A 3,000-year-old Chinese proverb says, “To protect your rivers, protect your mountains.” See an animation based on this figure at CengageNOW. Question: How might a drought in this area make these effects even worse?
Fig a, p. 339

83. Case Study: Living Dangerously on Floodplains in Bangladesh
Dense population
Located on coastal floodplain
Moderate floods maintain fertile soil
Increased frequency of large floods
Effects of development in the Himalayan foothills
Destruction of coastal wetlands

84. We Can Reduce Flood Risks
Rely more on nature’s systems
Wetlands
Natural vegetation in watersheds
Rely less on engineering devices
Dams
Levees

85. Solutions: Reducing Flood Damage

86. Active Figure: Effects of deforestation