8-1 Will We Have Enough Usable Water

MILLER/SPOOLMAN, SUSTAINING THE ENVIRONMENT, 12E

CHAPTER SUMMARY

CHAPTER 8

8-1 Will we have enough usable water?

The management of the world’s water supply is a huge 21st century challenge. Water is not equally available around the world; the location of the water, the type of water, and the demand for it all stress available water supplies. CONCEPT 8-1A We are using available freshwater unsustainably by wasting it, polluting it, and charging too little for this irreplaceable natural resource. CONCEPT 8-1B One of every six people do not have sufficient access to clean water, and this situation will almost certainly get worse.

1. Briefly describe the earth's water supply and its distribution. How does water flow through the hydrologic cycle? How does human activity interfere with the hydrologic cycle?
2. How much of the world's reliable runoff do we use? What impact will predicted population increases have on our water use? Describe two areas in the world with significant water scarcity.

8-2 How can we increase water supplies?

Water supplies can be increased by building dams, transferring water from high water areas to low water areas, withdrawing groundwater, and desalination. CONCEPT 8-2 Pumping groundwater, building dams, transferring water, and desalination can all increase water supplies, but these strategies all create environmental problems.

3.Briefly describe three major water problems. Evaluate which of these problems is of most concern in the United States and in the region in which you live.

4. Evaluate increasing the water supply through use of dams and water transfer projects. Compare the advantages and disadvantages of increasing the water supply through use of groundwater, desalination, and water transfer.

8-3 How can we use water more sustainably?

A blue revolution must take place in order to conserve water; two-thirds of the water that we have available is wasted through evaporation, leaks, overuse in irrigation, etc. CONCEPT 8-3 We can use water more sustainability if we cut water waste, raise water prices, slow population growth, and protect aquifers, forests, and other ecosystems that store and release water.

1. State how much water is wasted. Briefly describe measures that can be taken to reduce water losses through irrigation, industry, and home use.
2. What is one significant change you can make to conserve water? What would be the impact of increasing the cost of water on water use?

8-4 How can we reduce the threat of flooding?

Natural flooding by streams produces rich floodplains and recharges groundwater supplies. Increased human activities in active floodplains have contributed to the significant damage and destruction that result from floods. Concept 8-4 We can improve flood control by protecting wetlands and natural vegetation in watersheds and by not building in areas subject to frequent flooding.

1. What are the factors that have led to flooding disasters in Bangladesh?
2. Describe ways to mitigate flood risks. What inherent risks are present in those approaches to flood control?

8-5 What are the causes and effects of water pollution?

Both single sources and dispersed sources contribute to water pollution. Dispersed (nonpoint) sources are the most difficult to control. CONCEPT 8-5 Water pollution, which is caused mostly by agricultural activities, industrial facilities, and mining, and worsened by growth in population and resource use, causes illness and death in humans and other species and disrupts ecosystems.

1. List eight common types of water pollutants and give an example of each. Distinguish between point and nonpoint sources of pollution.
2. How many people lack access to clean drinking water in the world? What is the impact of contaminated drinking water?

8-6 What are the major water pollution problems in streams and lakes?

The ability of streams and lakes to naturally recover from pollution depends primarily on flow rate and the type of pollutant. CONCEPT 8-6 Addition of pollutants and excessive nutrients to streams and lakes can disrupt these ecosystems, and prevention of such pollution is more effective and less costly than cleaning it up.

11.Draw an oxygen sag curve to illustrate what happens to dissolved oxygen levels in streams below points where degradable oxygen-demanding wastes are added.

12.Compare problems of lake water pollution to those of stream pollution. List three ways to prevent cultural eutrophication and three ways to clean up cultural eutrophication. Summarize the state of the Great Lakes.

8-7 What are the major pollution problems affecting groundwater and other drinking water sources?

The properties of groundwater (location, flow rate, temperature, etc.) make it extremely difficult to detect sources of pollutants or clean them up if it becomes contaminated. Bottled water has a significantly higher monetary and environmental cost without the assurances of cleaner water. CONCEPT 8-7 Chemicals used in agriculture, industry, transportation, and homes can spill and leak into groundwater and make it undrinkable; polluted water can be purified, but protecting it through pollution prevention is the least expensive and most effective strategy.

13. List the major pollutants of groundwater and three ways to control groundwater pollution.

14. Summarize ways to purify drinking water.

8-8 What are the major water pollution problems affecting oceans?

Much of the world's population lives on the coast, and with that comes significant pollution. As populations rise, ocean pollution may increase significantly with increased human activity. CONCEPT 8-8 The great majority of ocean pollution originates on land and includes oil and other toxic chemicals and solid waste, which threaten fish and wildlife and disrupt marine ecosystems; the key to protecting oceans is to reduce the flow of pollutants into coastal waters.

15.Compare freshwater pollution to ocean pollution. List three ways to protect coastal waters.

8-9 How can we best deal with water pollution?

Many of the regulations that have reduced point-source pollution in developed countries (like the U.S.) were largely the result of bottom-up political pressure. The most important next step in controlling water pollution is to minimize it or prevent it altogether. Developing countries, in particular, need specific assistance to shift to pollution prevention. CONCEPT 8-9 Reducing water pollution requires preventing it, working with nature in treating sewage, cutting resource use and waste, reducing poverty, and slowing population growth.

16.Briefly describe two major laws that protect water quality in the United States. Outline the arguments for and against strengthening the Clean Water Act.

17. Briefly describe and distinguish among septic tanks, primary, secondary, and advanced sewage treatment. Describe biologist John Todd's approach to sewage treatment.