1. Environmental Science Inquiry and Applications Cunningham • Cunningham
Principles of
Environmental Science
Inquiry and Applications
Third Edition
Cunningham • Cunningham
Chapter 10 Lecture Outlines*
*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.
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2. Water: Resources and Pollution
Chapter 10

3. WATER RESOURCES
Hydrologic Cycle: 1. Amount stays the same, but water moves from place to place
Describes the circulation of water as it:
Evaporates from land, water, and organisms. (2. Transpires from plants)
Enters the atmosphere.
Condenses and precipitates back to the earth’s surfaces.3. 10%
Moves underground by infiltration or overland into rivers, lakes and seas.

4. 4. Renewable water:
Water infiltration into accessible aquifers.

5. Mean Annual Precipitation

6. Water Distribution

7. MAJOR WATER COMPARTMENTS
5.Residence time: time water stays in compartment
Largest fresh water compartment: 6. ice & snow
Groundwater
Second largest reservoir of fresh water.
7. Infiltration - Process of water percolating through the soil and into fractures and permeable rocks.
Zone of 8. Aeration - Upper soil layers that hold both air and water.
Zone of 9.Saturation - Lower soil layers where all spaces are filled with water.
10. Water Table - Top of Zone of Saturation

8. Groundwater

9. Groundwater
11.Aquifers - Porous layers of sand, gravel, or rock lying below the water table.
Artesian - Pressurized aquifer intersects the surface.(12.Water flows w/out pumping)
13. Recharge Zone - Area where water infiltrates into an aquifer.
Recharge rate is often very slow.
Presently, groundwater is being removed faster than it can be replenished in many areas.

10. Figure 10.06

11. MAJOR WATER COMPARTMENTS CONT’D
Rivers and Streams
Precipitation that does not evaporate or infiltrate into the ground runs off the surface, back toward the sea.
14) 0.1% of global water is accessible fresh
Best measure of water volume carried by a river is 15.discharge.
The amount of water that passes a fixed point in a given amount of time.
Usually expressed as cubic feet per second. 16)Ft3/sec

12. MAJOR WATER COMPARTMENTS CONT’D
Wetlands
Play a vital role in hydrologic cycle.
Lush plant growth stabilizes soil and retards surface runoff, allowing more aquifer infiltration.
Disturbance reduces natural water-absorbing capacity, resulting in 17.floods & erosion in wet periods,
& less water flow the rest of the year.

13. MAJOR WATER COMPARTMENTS CONT’D
The Atmosphere
Among the smallest water reservoirs.
Contains 0.001% of total water supply.
Has most rapid turnover rate.
Provides mechanism for distributing fresh water over landmasses and replenishing terrestrial reservoirs.

14. WATER AVAILABILITY AND USE
Total freshwater for humans?18 Less than1%
Renewable Water Supplies
Made up of surface runoff and infiltration into accessible freshwater aquifers.
Water-Rich ad Water-Poor Countries
Water availability usually measured in terms of 19.renewable water per capita.
Highest per capita generally found in countries with moist climates and low population densities.

15. Water Use
Increasing worldwide. Why? 20. Each person is using MORE water.
Withdrawal - Total amount of water taken from a source.
Consumption - Fraction of withdrawn water made unavailable for other purposes
21. (Not returned to its source).
22. Degradation - Change in water quality due to contamination making it unsuitable for desired use.

16. Quantities of Water Used
Water use has been increasing twice as fast as population growth over past century.
Worldwide, 23. agriculture, especially in poor countries, claims about 70% of total water withdrawal. In many developing countries, agricultural water use is extremely inefficient & highly consumptive.
24. Drip irrigation is a good alternative.
Worldwide, industry accounts for about 25% of all water use.
25.Cooling water for power plants is single largest industrial use.

17. Figure 10.10

18. Water Withdrawal

19. FRESHWATER SHORTAGES
Colorado River Basin: area in the U.S. consuming more water than can be renewed: The Southwest
Estimated 1.5 billion people lack access to an adequate supply of drinking water.
3 billion lack acceptable sanitation.
A country where consumption exceeds more than 20% of available, renewable supply is considered vulnerable to water stress.
Globally, water supplies are abundant, but, along with capital resources, are unevenly distributed.

20. A Precious Resource
Region with the highest water demand:
27. Arid & Semiarid
Currently, 45 countries, most in Africa or Middle East, cannot meet the minimum essential water requirements of their citizens.
More than two-thirds of world’s households retrieve water from outside the home.
Availability does not automatically equate to affordability.
Sanitation levels decline when water is expensive.

21. Figure 10.12

22. Depleting Groundwater
Groundwater is the source of nearly 40% of fresh water in the U.S.
On a local level, withdrawing water faster than it can be replenished leads to a cone of depression in the water table,
On a broader scale, heavy pumping can deplete an aquifer. Greatest use: AG
Unconfined aquifer: groundwater recharged by surface water above. 28.Trickle irrigation: AG conservation

23. Figure 10.11

24. Ogallala Aquifer
29. Largest groundwater deposit in the world.

25. Depleting Groundwater

26. Depleting Groundwater Cont’d
Withdrawing large amounts of groundwater in a small area causes porous formations to collapse, resulting in subsidence.
Sinkholes form when an underground channel or cavern collapses.
30. Saltwater intrusion can occur along coastlines where overuse of freshwater reservoirs draws the water table low enough to allow saltwater to intrude.

27. INCREASING WATER SUPPLIES
Seeding Clouds
Condensation Nuclei
Towing Icebergs
Cost
Desalination
Most common methods are distillation and reverse osmosis.
Three to four times more expensive than most other sources.

28. INCREASING WATER SUPPLIES CONT’D
Dams, Reservoirs, and Canals - Trap excess water in areas of excess and transfer it to areas of deficit.
Environmental Costs
Upsets natural balance of water systems.
Ecosystem Losses
Loss of wildlife habitat.
Reservoir Size
Water Quality

29. Figure 10.14

30. Benefits of dams
31.
1) Generate electricity
2) Flood control
3) Recreation
4) Year-round water supply

31. Dams, Reservoirs, and Canals
Displacement of People
Three Gorges Dams in China will force relocation of over a million people.
Evaporation, Leakage, Siltation
Evaporative losses from Lake Mead and Lake Powell on the Colorado River is about 1km3 per year (264 billion gallons).
Dams slow water flow, allowing silt (nutrients) to drop out.
Loss of Free-Flowing Rivers

32. Figure 10.15

33. Price Mechanisms and Water Policy
Throughout most of U.S. history, water policies have generally worked against conservation.
Eastern - Riparian Use Rights
Western - Prior Appropriation Rights
In most federal reclamation projects, customers have been charged only for the immediate costs of water delivery.

34. WATER MANAGEMENT AND CONSERVATION
Watershed Management
Watershed – 32. All the land drained by a stream or river. .

35. Retaining vegetation and ground cover helps retard rainwater and lessens downstream flooding.
Xeroscaping: yard worked w/ endemic species needing little water & more rocks.
Additionally, retaining crop residue on fields reduces flooding and minimizing plowing and forest cutting on steep slopes protects watersheds

36. Figure 10.16

37. Why are floods more destructive?
33. We build on the floodplain.

38. Domestic Conservation
Estimates suggest many societies could save as much as half of current domestic water usage without great sacrifice or serious change in lifestyle.
Largest domestic use is toilet flushing.
Small volume of waste in large volume of water.
Significant amounts of water can be reclaimed and recycled.
Purified sewage effluent

39. WATER POLLUTION
Any physical, biological, or chemical change in water quality that adversely affects living organisms can be considered pollution.
34.Point Sources - Discharge pollution from specific locations.
Factories, power plants, oil wells
Non-Point Sources - Scattered or diffuse, having no specific location of discharge.
35.Agricultural fields, feedlots, golf courses
Atmospheric Deposition

40. Infectious Agents
Main source of waterborne pathogens is untreated and improperly treated human waste.
Animal wastes from feedlots and fields is also an important source of pathogens.
In developed countries, sewage treatment plants and pollution-control devices have greatly reduced pathogens.
Coliform bacteria - Intestinal bacteria.
Escherichia coli (E. coli)

41. E. coli
Good indicator of sewage in water.
36. Add chlorine to kill pathogens: chlorination

42. Oxygen-Demanding Wastes
Water with an oxygen content > 6 ppm will support desirable aquatic life.
Water with < 2 ppm oxygen will support mainly detritivores and decomposers.
Oxygen is added to water by diffusion from wind and waves, and by photosynthesis from green plants, algae, and cyanobacteria.
Oxygen is removed from water by respiration and oxygen-consuming processes.

43. Oxygen-Demanding Wastes Cont’d
Biochemical Oxygen Demand - Amount of dissolved oxygen 37.consumed by aquatic microorganisms.
Dissolved Oxygen Content - Measure of dissolved oxygen in the water.
Effects of oxygen-demanding wastes on rivers depend on volume, flow, and temperature of river water.
38.Oxygen Sag - Oxygen levels decline downstream from a pollution source as decomposers metabolize waste materials.

44. Oxygen Sag

45. Plant Nutrients and Cultural Eutrophication
39.Oligotrophic - Bodies of water that have clear water and low biological productivity.
40. Eutrophic - Bodies of water that are rich in organisms and organic material.
Eutrophication - Process of increasing nutrient levels and biological productivity.
41.Cultural Eutrophication - Increase in biological productivity and ecosystem succession caused by human activities.

46. Toxic Tides
Excessive nutrients support blooms of deadly aquatic microorganisms in polluted waters.
Increasingly common where nutrients and wastes wash down rivers.
Pfiesteria piscicida is a poisonous dinoflagellate recognized as killer of fish and shellfish in polluted rivers and estuaries.

47. Inorganic Pollutants
Metals
Many metals such as mercury, lead, cadmium, and nickel are highly toxic.
Highly persistent and tend to bioaccumulate in food chains.
Mercury released from incinerators and coal-burning power plants is the most widespread toxic metal contamination in North America.
Mine drainage and leaching are serious sources of environmental contamination.

48. Inorganic Pollutants Cont’d
Nonmetallic Salts
Many salts that are non-toxic at low concentrations can be mobilized by irrigation and concentrated by evaporation, reaching levels toxic to plants and animals.
Leaching of road salts has had detrimental effect on many ecosystems.
Acids and Bases
Often released as by-products of industrial processes.

49. Organic Chemicals
Thousands of natural and synthetic organic chemicals are used to make pesticides, plastics, pharmaceuticals, pigments, etc.
Two most important sources of toxic organic chemicals in water are:
Improper disposal of industrial and household wastes.
Runoff of pesticides from high-use areas.
Fields, roadsides, private lawns

50. Sediment
Human activities have accelerated erosion rates in many areas.
Cropland erosion contributes about 25 billion metric tons of suspended solids to world surfaces each year.
Sediment can either be beneficial (nourish floodplains) or harmful (smother aquatic life).

51. 42. Thermal Pollution
Raising or lowering water temperatures from normal levels can adversely affect water quality and aquatic life.
Oxygen solubility in water decreases as temperatures increase.
Species requiring high oxygen levels are adversely affected by warming water.

52. Thermal Pollution Cont’d
Industrial cooling often use heat-exchangers to extract excess heat, and discharge heated water back into original source.
Thermal Plume
Produce artificial environments which attract many forms of wildlife.

53. WATER QUALITY TODAY
Areas of Progress
43.Clean Water Act (1972) established a National Pollution Discharge Elimination System, which requires a permit for any entity dumping wastes in surface waters.
In 2003, EPA reported 91% of all monitored river miles and 88% of all accessed lake acres are suitable for their designated uses.
Most progress due to municipal sewage treatment facilities.

54. Water Quality Today

55. Watershed Approaches
In 1998, EPA switched regulatory approaches. Rather than issue standards on a site by site approach, the focus is now on watershed-level monitoring and protection.
States are required to identify waters not meeting water quality goals and develop total maximum daily loads (TMDL) for each pollutant and each listed water body.

56. Remaining Problems
Greatest impediments to achieving national goals in water quality are sediment, nutrients, and pathogens, especially from non-point discharges.
About three-quarters of water pollution in the U.S. comes from soil erosion, air pollution fallout, and agricultural and urban runoff.
Single cow produces 30 kg manure/day.
Some feedlots have 100,000 animals.

57. Problems and Progress in Other Countries
Sewage treatment in wealthier countries of Europe generally equal or surpass the U.S.
In Russia, only about half of the tap water supply is safe to drink.
In urban areas of South America, Africa, and Asia, 95% of all sewage is discharged untreated into rivers.
Two-thirds of India’s surface waters are contaminated sufficiently to be considered dangerous to human health.

58. Groundwater Pollution
About half the U.S. population, and 95% of rural residents, depend on underground aquifers for drinking water.
For decades, groundwater was assumed impervious to pollution and was considered the gold standard for water quality.
Estimated 1.5 million Americans fall ill from fecal contamination annually.
Cryptosporidium outbreaks

59. Groundwater and Drinking Water
EPA estimates 4.5 trillion liters of contaminated water seep into the ground in the U.S. every day.
MTBE - Gasoline additive, and suspected carcinogen, is present in many urban aquifers.
In agricultural areas, fertilizers and pesticides commonly contaminate aquifers and wells.

60. Groundwater Pollution

61. Ocean Pollution
Estimated 6 million metric tons of plastic bottles, packaging material, and other litter tossed from ships into the ocean annually.
Few coastlines in the world remain uncontaminated by oil or oil products.

62. Ocean Pollution

63. POLLUTION CONTROL
Source Reduction
Cheapest and most effective way to reduce pollution is avoid producing it or releasing it into the environment.
Studies show as much as 90% less road salt can be used without significantly affecting winter road safety.
Soil Conservation
Banning phosphate detergents

64. Sewage Treatment
More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water.
Natural Processes
In many areas, outdoor urination and defecation is the norm.
When population densities are low, natural processes can quickly eliminate waste.

65. Municipal Sewage Treatment
Primary Treatment - Physical separation of large solids from the waste stream.
Secondary Treatment – 44. Biological degradation of dissolved organic compounds.
Effluent from primary treatment transferred into trickling bed, or aeration tank
Effluent from secondary treatment is usually disinfected (45.chlorinated) before release into nearby waterway.

66. Municipal Sewage Treatment Cont’d
Tertiary Treatment - Removal of plant nutrients (nitrates and phosphates) from secondary effluent.
Chemicals, or natural wetlands.
In many US cities, sanitary sewers are connected to storm sewers.
Heavy storms can overload the system, causing by-pass dumping of raw sewage and toxic runoff directly into watercourses.

67. Municipal Sewage Treatment

68. Low-Cost Waste Treatment
Artificial Wetlands
Natural water purification
Effluent can be used to irrigate crops or raise fish for human consumption.

69. Water Remediation
Containment methods confine liquid wastes in place, or cap surface with impermeable layer to divert water away from the site.
Extraction techniques are used to pump out polluted water for treatment.
Oxidation, reduction, neutralization, or precipitation.
Living organisms can also be used effectively to break down polluted waters.

70. WATER LEGISLATION
Clean Water Act (1972)
Goal was to return all U.S. surface waters to “fishable and swimmable” conditions.
For Point Sources, Discharge Permits and Best Practicable Control Technology are required.
Set zero discharge for 126 priority toxic pollutants.

71. Clean Water Act (1972)
Areas of Contention
Draining or Filling of Wetlands
Many consider this taking of private land.
Un-funded Mandates
State or local governments must spend monies not repaid by Congress.

72. Summary:
Hydrologic Cycle
Water Compartments
Water Availability
Freshwater Shortages
Increasing Water Supplies
Water Management and Conservation
Water Pollution
Water Quality Today
Water Pollution Control
Water Legislation