11.2 PBL
1. What is meant by the phrase “We all live downstream”?
a. Changes in the water supply (quantity and quality) affect everything downstream.
2. Rank the three main uses of water worldwide from greatest to least?
a. agriculture, industrial, residential
3. Look at the figure on page 297 that compares world water usage. Explain the differences between water use in the
United States and that of Asia.
a. Asia uses much more water for agriculture and the US uses much more water for industrial purposes.
4. What poisonous elements do water treatment facilities remove from water?
a. mercury, arsenic, and lead
5. What are 4 different types of pathogens that must be removed from water during water treatment?
a. bacteria, viruses, protozoa, and parasitic worms.
6. Under what conditions is the process of irrigation used?
a. Dry areas with a lack of rainfall.
7. Why is the most common method of irrigation in the United States considered to be inefficient?
a. Because most of the water coming from the high-pressure overhead sprinklers will evaporate before ever
reaching the roots of the plants.
8. Why are water diversion projects being implemented in the desert regions of the United States?
a. To provide water from the rivers to the dry areas.
9. What problem has water diversion created with the Colorado River?
a. It no longer runs into the Gulf of California (except during very wet years).
10. List 4 advantages and 3 disadvantages of building dams.
a. Advantages : Flood control, drinking water, irrigation, recreation, and industry (any 4)
b. Disadvantages: People displaced, ecosystems destroyed, fertile sediment stays behind the dam making
farmland less productive downstream, dam failure can cause flooding (any 3)
11. Describe water conservation efforts in agriculture, industry, and in homes.
a. Agriculture: drip irrigation systems offer small amounts of water directly to the plant roots to prevent
evaporation, seepage, and runoff.
b. Industry: recycling of cooling water and wastewater rather than discharging water into rivers
c. In homes: low-flow toilets and shower heads reduce household water use; watering landscapes at night to
avoid evaporation
12. Desalination offers some hope as a possible solution to our freshwater shortage. What are 2 disadvantages of this
solution?
a. Expensive to build the plants and the plants use large amounts of energy.
13. What are the 6 steps in water treatment?
a. first filtration removes large debris
b. coagulation (alum is added to the water to goop up into flocs that attract bacteria and impurities) causes
impurities to fall to the bottom
c. second filtration filters remaining impurities using sand, gravel, and hard coal
d. chlorination prevents new bacterial growth
e. aeration helps release unwanted gases to reduce odor and improve taste
f. Additional treatment with fluoride, sodium, lime
11.2 PBL
1. What is meant by the phrase “We all live downstream”?
2. Rank the three main uses of water worldwide from greatest to least?
3. Look at the figure on page 297 that compares world water usage. Explain the differences between water use in the
United States and that of Asia.
4. What poisonous elements do water treatment facilities remove from water?
5. What are 4 different types of pathogens that must be removed from water during water treatment?
6. Under what conditions is the process of irrigation used?
7. Why is the most common method of irrigation in the United States considered to be inefficient?
8. Why are water diversion projects being implemented in the desert regions of the United States?
9. What problem has water diversion created with the Colorado River?
10. List 4 advantages and 3 disadvantages of building dams.
11. Describe water conservation efforts in agriculture, industry, and in homes.
12. Desalination offers some hope as a possible solution to our freshwater shortage. What are 2 disadvantages of this
solution?
13. What are the 6 steps in water treatment?
11.2 PBL
1. What is meant by the phrase “We all live downstream”?
2. Rank the three main uses of water worldwide from greatest to least?
3. Look at the figure on page 297 that compares world water usage. Explain the differences between water use in the
United States and that of Asia.
4. What poisonous elements do water treatment facilities remove from water?
5. What are 4 different types of pathogens that must be removed from water during water treatment?
6. Under what conditions is the process of irrigation used?
7. Why is the most common method of irrigation in the United States considered to be inefficient?
8. Why are water diversion projects being implemented in the desert regions of the United States?
9. What problem has water diversion created with the Colorado River?
10. List 4 advantages and 3 disadvantages of building dams.
11. Describe water conservation efforts in agriculture, industry, and in homes.
12. Desalination offers some hope as a possible solution to our freshwater shortage. What are 2 disadvantages of this
solution?
13. What are the 6 steps in water treatment?