1. Chapter 15 Water Resources
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 15

2. Chapter 15 Key Concepts The physical properties of water
Availability of fresh water
Methods of increasing freshwater supplies
Using water more efficiently
Problems associated with flooding

3. Sections 1 and 2 Key Ideas Why is water so important?
What makes water unique?
How much fresh water is available to humans?
What are some of the sources of fresh water?
How do we use the world’s fresh water?
What are some water resource issues faced in the United States?

4. Water’s Importance No species can live without water.
Plays a key role in shaping the earth’s surface, moderating climate, removing and diluting wastes.
Takes huge amount to provide food, shelter and other needs.
71% of our planet

5. Water’s Unique Properties
Hydrogen bonding: water’s unique properties comes from the strong attractive forces between molecules.

6. Water’s Unique Properties
Liquid over wide temperature range: without its high boiling point the oceans would have evaporated long ago.
Changes temperature slowly: high specific heat means slow temperature changes. Helps moderate climate.

7. Water’s Unique Properties
High heat of evaporation: evaporation takes a lot of heat. This explains why sweating makes you feel cooler.
Great dissolving power: known as the universal solvent because so may things dissolve well in it. Leads to pollution problems as well.

8. Water’s Unique Properties
Filters out ultraviolet radiation: protecting aquatic organisms from sun’ rays.
Adhesion and cohesion: strong forces of attraction between molecules allows water to rise up inside plants from roots to leaves.

9. Water’s Unique Properties
Expands when it freezes: most substances contract when frozen, not water. Water expands and is less dense in its solid form. Hence, ice floats.
Water is also one of few substances found commonly as a solid, liquid and gas.

10. How Much Water Is Available?
71% of earth is water
97.4% of that is in oceans
Most of the remaining 2.6% is in ice caps and glaciers.
Only about 0.014% is easily available fresh water.
If earth’s water was 26 gallons, 2.5 teaspoons would be available.

11. Supply of Water

12. Supply of Water Resources
Freshwater
Readily accessible freshwater
Biota
0.0001%
Rivers
Atmospheric
water vapor
Lakes
0.0007%
Soil
moisture
0.0005%
Groundwater
0.592%
Ice caps
and glaciers
0.014%
Fig p. 307

13. Water Cycle: Renewing Water

14. Surface Water
Surface runoff: precipitation that does not infiltrate the ground or return to the atmosphere.
Reliable runoff: the amount of water that can be counted on each year as a stable source.

15. Surface Runoff
Watershed: the region of land from which surface water drains into a river, lake, wetland or other body of water

16. Watershed

17. Delaware
River
Watershed

19. Groundwater One of the most important source of water.
Precipitation filters down through pores and cracks in soil and rocks.
Groundwater found within 1km of the surface contains 100 times more water than all the rivers, streams and lakes

20. Evaporation and transpiration
Ground Water
Evaporation and transpiration
Evaporation
Stream
Infiltration
Water table
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Less permeable material
such as clay
Confirming permeable rock layer
Fig p. 308

21. Use of Water Resources Humans use about 54% of reliable runoff
United States
Industry 11%
Public 10%
Power
cooling
38%
Agriculture
Agriculture: worldwide about 70% of water is used to irrigate crops.
85% of that is not returned to the water ways.
Fig p. 309

22. Use of Water Resources
Industry: 20% of water withdrawn each year is used by industry.
Domestic: 10% is used by cities and residencies.

23. Uses of Water

24. Water in US East vs. West
Eastern US most water is used for energy production, manufacturing.
Western US most water is used for irrigation.

25. Water in US East vs. West

26. Chapter 15 Sections 1-2 Review
Where is the world’s usable water located?
Describe several properties of water that make it unique.
How much water is available for human usage?
What is runoff? What is a watershed? What is groundwater?
Describe the water cycle.
How is most of the world’s water used?
What are some water differences between the eastern and western US?

28. Key Concepts Chapter 15 Sections 3, 4 and 5
What causes fresh water shortages?
How many people do not have access to clean water?
How can we increase clean water supplies?
What are advantages and disadvantages of large dams and reservoirs?
Case Studies: 1) Water Conflicts in the Middle East, 2) Colorado River Basin, 3) China’s Three Gorges Dam, 4) Aral Sea, 5) California Water Transfer, 6) Canada’s James Bay Watershed.

29. Access to Freshwater
About 1 in 6 people (1 billion people) do not have access to regular, clean water supplies.

30. Too Little Water What causes fresh water shortages? Acute shortage
Adequate supply
Shortage
Metropolitan regions with population greater than 1 million
Fig p. 310

31. Areas of US where there are conflicts over water
Areas of US where there are conflicts over water. “Water Wars” competing for a scarce resource.

32. Too Little Water: 4 Reasons
Dry climate: people living or growing crops in areas where little precipitation naturally falls
San Diego averages just 8 inches of rain a year compared to over 35 inches in Camden.
Las Vegas averages less than 5 inches of rain yearly.

33. Too Little Water
Drought: prolonged periods of below average precipitation.

34. Too Little Water
Desiccation: drying of exposed soil because of activities such as deforestation and overgrazing.

35. Too Little Water
Water stress: low per capita availability of water due to increasing population demands.
Some regions get plenty of water, but not near where people live
Some regions get plenty of water, but not at the right time of year
Some regions have no capacity to store water.

36. Natural Capital Degradation. Stress on the world’s river basins.

37. Increasing Water Supplies
Build dams and reservoirs
Transfer water to places it is needed
Withdraw groundwater
Desalinization
Reduce water waste
Import food from regions where irrigation is not needed.

38. Using Dams and Reservoirs
Large dams can produce cheap electricity, reduce downstream flooding and provide a year-round source of water, but they completely alter the river ecosystem.

41. Using Dams and Reservoirs to Supply More Water: The Trade-offs
Large losses
of water through
evaporation
Flooded land destroys forests or cropland and
displaces people
Downstream flooding is reduced
Downstream cropland and
estuaries are deprived of
nutrient-rich silt
Reservoir is useful for recreation and fishing
Can produce cheap electricity (hydropower)
Migration and spawning of some fish are disrupted
Provides water
for year-round
irrigation of
cropland
Fig p. 313

42. Transferring Water from One Place to Another
Watershed transfer
North Bay
Aqueduct
South Bay
California Aqueduct
CALIFORNIA
NEVADA
UTAH
MEXICO
Central Arizona
Project
Colorado River
Los Angeles
Shasta Lake
Sacramento
Fresno
Phoenix
Tucson
ARIZONA
Colorado
River
San Francisco
San Diego
California Water Project
Central Arizona Project
James Bay
Fig p. 317

43. Sections 3,4 and 5 Review What causes fresh water shortages?
How can we increase clean water supplies?
What are advantages and disadvantages of large dams and reservoirs?
Case Studies: 1) Water Conflicts in the Middle East, 2) Colorado River Basin, 3) China’s Three Gorges Dam, 4) Aral Sea, 5) California Water Transfer, 6) Canada’s James Bay Watershed.

45. Key Concepts Chapter 15 Sections 6 and 7
What are advantages and disadvantages of using groundwater?
Deep water or shallow water aquifers, what about desalinization?
“Weird” Water Solutions?
What are the benefits of reducing water waste?
How can we reduce wasting irrigation water? What about in homes, industry and businesses?

46. Tapping Groundwater: Benefits
Most aquifers are renewable sources unless the water is removed faster than it is replenished

47. Tapping Groundwater: Benefits
Year-round use: aquifers provide reliable year-round use.
¼ of world’s drinking water
In US groundwater is being withdrawn 4 times its replacement rate.

48. Tapping Groundwater: Benefits
Little Water Loss: there is no loss of water due to evaporation.
Often Cheaper: groundwater is often cheap to extract.

49. Tapping Groundwater: Costs
Using ground water has tradeoffs.
Water tables around the world are falling.

50. Problems Using Groundwater

52. Problems with Using Groundwater
Water table lowering
Depletion
Subsidence
Saltwater intrusion
Chemical contamination
Reduced stream flows

54. Potential Sources of Groundwater Contamination

55. Problems with Using Groundwater
As groundwater is pumped out of the ground, the ground may subside.
This picture shows ground subsidence in CA.

56. Problems Using Groundwater
Salt Water Intrusion: As water is pumped out of ground, saltwater can move inland to “pollute” the well.

57. Problems Using Groundwater

58. Increasing Water Supplies
Distillation desalination: removing salt from seawater by evaporation of water leaving salt behind.

59. Increasing Water Supplies
Reverse osmosis desalination: pumping saltwater under high pressure through a membrane to take out salt.

60. Increasing Water Supplies
Desalination is very expensive: only several oil-rich and water poor countries use large-scale desalinization.
TAKES TREMENDOUS AMOUNT OF ENERGY
Future Potential???

61. Increasing Water Supplies
Cloud Seeding: releasing tiny particles into air to produce rain clouds.
Towing Icebergs: moving ice around world.
Using Oil Tankers Filled with water.

62. Using Water More Efficiently
Reduce losses due to leakage: we waste about 2/3rd of the water we use, but simple steps could reduce that to 15%.

63. Using Water More Efficiently
Reform water laws:
Higher water prices
Typically US farmers only pay 1/5th of true water costs.
Encouraging conservation
Reward people for using less water

64. Using Water More Efficiently
Improve irrigation efficiency: 60% of water applied to land does not reach crops.
Evaporation
Seepage
Runoff

65. Using Water More Efficiently
Improve irrigation efficiency:
Center pivot sprinklers
Time controlled irrigation
Soil moisture detectors
Drip Irrigation

68. Using Water More Efficiently
Water efficient landscaping (xeriscaping): using vegetating that does not require much water.
About 1/5th of all US water houses do not have water meters and pay a flat rate.

69. Using Water More Efficiently
Water efficient appliances:
Low Flow Toilets
Washers that use less water
Reusing water:
Using “brownwater” for non-drinking water usages.

71. Chapter 15 Sections 6, 7 Review
What are advantages and disadvantages of using groundwater?
Deep water or shallow water aquifers, what about desalinization?
“Weird” Water Solutions?
What are the benefits of reducing water waste?
How can we reduce wasting irrigation water? What about in homes, industry and businesses?

73. Chapter 15 Section 8 and 9 What causes flooding?
How do humans exacerbate flooding?
How can flood risks be minimized?
What are solutions for sustainable water use?

74. Too Much Water: Floods Natural phenomena
Aggravated by human activities
Natural floodplain, altered floodplain and flooded.
Reservoir
Dam
Levee
Flood
wall
Floodplain
Fig p. 327

75. Too Much Water: Floods
Natural Events: heavy rainfall, melting snow are major causes of flooding.
Floodplain: the natural area around a river where flooding normally occurs.

76. Too Much Water: Floods
Floodplains are usually fertile, have ample water for irrigation and therefore often developed.
Floods bring nutrients onto surrounding land.

78. Too Much Water: Floods Flooding Worsens With Human Impacts:
Removing wetlands
Building levees
Making more land impermeable (development)

79. Downstream Impacts

80. Too Much Water: Floods Reducing Risks: Channelization Floodwalls
Build Dams
Preserve wetlands
Identify and restrict building in floodplains
Restore natural land

83. Solutions: Achieving a More Sustainable Water Future
Efficient irrigation
Water-saving technologies
Improving water management
See Fig p. 329