activated-sludge sewage
      treatment 359
aquiclude 341
aquifer 341
aquitard 341
artesian well 342
biochemical oxygen demand
      (BOD) 349
confined aquifer 341
domestic water 344
eutrophication 350
evapotranspiration 341
fecal coliform bacteria 351
groundwater 341 		groundwater mining 361
hydrologic cycle 341
industrial water use 346
in-stream water use 347
irrigation 345
limiting factor 350
nonpoint source 350
point source 350
porosity 342
potable waters 340
primary sewage treatment 358
runoff 341
salinization 361
secondary sewage treatment 358 		sewage sludge 359
storm-water runoff 356
tertiary sewage treatment 360
thermal pollution 353
trickling filter system 358
unconfined aquifer 341
vadose zone 341
water diversion 357
water table 341

On-line Flashcards
      Supposedly, the importance of wetlands is understood, but the problems of wetland destruction continue. Check out Stronger Wetland Protection Rules Announced and The Prairie Wetlands of Southwest Minnesota for recent updates on wetlands protection.
      Do you know where your drinking water comes from? Is your local source ground or surface water? A detailed explanation of the source of Memphis, Tennessee's water supply is provided in Drinking Water from Wells, Not from the River.
      The importance of protecting groundwater from contamination is highlighted in the Protecting Groundwater Resources case study.
      Water diversions, the mining of groundwater, and politically charged situations . . . realities when water is a scarce resource. Check out Historic Agreement on Water Allotments in Southern California and Drought Focuses on Long-standing Water Disputes in the Middle East to learn more about conflicts that result from the lack of water. Although water is not scarce in the Great Lakes region, see why Low Water Levels in the Great Lakes are causing concerns in this area. 		      Restoration projects, protection, and funding for cleanup activities are just a few examples. Check out Everglades Restoration: Greatest Restoration Yet, or Just More of the Same? for an example of a restoration project.
      A variety of ways to clean up and improve water quality can be found in the following stories: International Accord to Clean Up the Rhine River, and Food Web Control of Primary Production in Lakes.
      Another way to improve water quality is to support local conservation measures. Look over American Heritage River System Created for details on how this program aims to help coordinate efforts to improve water quality.
      What is the link between fertilizer runoff and the green soupy lake in an adjacent area? Now is your chance to study it in more detail. Check out the Deoxygenation of Lakes animation for a better understanding of the process.       Normal rainfall is neutral . . . right? What causes acid rain? When is the effect of acid rain most apparent? Study the Acid Rain animation for answers to these questions and to see how acid rain affects aquatic ecosystems such as lakes.
Review Questions
  1. Describe the hydrologic cycle.
  2. Distinguish between withdrawal and consumption of water.
  3. What are the similarities between domestic and industrial water use? How are they different from in-stream use?
  4. How is land use related to water quality and quantity? Can you provide local examples?
  5. What is biochemical oxygen demand? How is it related to water quality?
  6. How can the addition of nutrients such as nitrates and phosphates result in a reduction of the amount of dissolved oxygen in the water?
  7. Differentiate between point and nonpoint sources of water pollution.

  1. How are most industrial wastes disposed of? How has this changed over the past 25 years?
  2. What is thermal pollution? How can it be controlled?
  3. Describe primary, secondary, and tertiary sewage treatment.
  4. What are the types of wastes associated with agriculture?
  5. Why is storm-water management more of a problem in an urban area than in a rural area?
  6. Define groundwater mining.
  7. How does irrigation increase salinity?
  8. What are the three major water services provided by metropolitan areas?
Critical Thinking Questions
  1. Leakage from freshwater distribution systems accounts for significant losses. Is water so valuable that governments should require systems that minimize leakage in order to preserve the resource? Under what conditions would you change your evaluation?
  2. Do non-farmers have an interest in how water is used for irrigation? Under what conditions should the general public be involved in making these decisions along with the farmers who are directly involved?
  3. Should the United States allow Mexico to have water from the Rio Grande and the Colorado Rivers, both of which originate in the United States and flow to Mexico?
  4. Do you believe that large scale hydroelectric power plants should be promoted as a renewable alternative to power plants that burn fossil fuels? What criteria do you use for this decision?
  1. What are the costs and what are the benefits of the proposed Garrison Diversion Unit? What do you think should happen with this project?
  2. How might you be able to help save freshwater in your daily life? Would the savings be worth the costs?
  3. Look at the hydrologic cycle in Figure 16.3. If global warming increases the worldwide temperature, how should increased temperature directly affect the hydrologic cycle?
  4. After reading the Issues & Analysis concerning the California Water Plan, do you believe water should be diverted from northern California to southern California?