1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Water Resources Objectives Describe the distribution of Earth’s water resources. Explain why fresh water is one of Earth’s limited resources. Describe the distribution of Earth’s surface water. Describe the relationship between groundwater and surface water in a watershed. Chapter 11

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Resources Water is essential to life on Earth. Humans can live for more than month without food, but we can live for only a few days without water. Two kinds of water found on Earth: Fresh water, the water that people can drink, contains little salt. Salt water, the water in oceans, contains a higher concentration of dissolved salts. Most human uses for water, such as drinking and agriculture, require fresh water. Chapter 11 Section 1 Water Resources

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Water Cycle Water is a renewable resource because it is circulated in the water cycle. The oceans are important because almost all of the Earth’s water is in the ocean. Chapter 11 Section 1 Water Resources

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Water Cycle Chapter 11 Section 1 Water Resources

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Global Water Distribution The fresh water we use comes mainly from lakes and rivers and from a relatively narrow zone beneath the Earth’s surface. Chapter 11 Section 1 Water Resources

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Surface Water Surface water is all the bodies of fresh water, salt water, ice, and snow, that are found above the ground. The distribution of surface water has played a vital role in the development of human societies. Chapter 11 Section 1 Water Resources

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Watersheds A watershed is the area of land that is drained by a water system. Chapter 11 Section 1 Water Resources

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Watersheds Chapter 11 Section 1 Water Resources

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Groundwater Most of the fresh water that is available for human use cannot be seen, as it exists underground. When it rains, some of the water that falls onto the land flows into lakes and streams. But much of the water percolates through the soil and down into the rocks beneath. Groundwater is the water that is beneath the Earth’s surface. Chapter 11 Section 1 Water Resources

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Aquifers An aquifer is a body of rock or sediment that stores groundwater and allows the flow of groundwater. The water table forms the upper boundary of an aquifer, and most aquifers consist of materials such as rock, sand, and gravel that have a lot of spaces where water can accumulate. Chapter 11 Section 1 Water Resources

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Porosity Porosity is the percentage of the total volume of a rock or sediment that consists of open spaces. Water in an aquifer is stored in the pore spaces and flows from one pore space to another. Chapter 11 Section 1 Water Resources

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Permeability Permeability is the ability of a rock or sediment to let fluids pass through its open spaces or pores. Materials such as gravel that allow the flow of water are permeable. Materials such as clay or granite that stop the flow of water are impermeable. The most productive aquifers usually form in permeable materials, such as sandstone, limestone, or layers of sand and gravel. Chapter 11 Section 1 Water Resources

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Wells A hole that is dug or drilled to reach groundwater is called a well. We dig wells because ground water may be a more reliable source of water than surface water and because water is filtered and purified as it travels underground. The height of the water table changes seasonally, so wells are drilled to extend below the water table. Chapter 11 Section 1 Water Resources

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Water Use and Management Objectives Identify patterns of global water use. Explain how water is treated so that it can be used for drinking. Identify how water is used in homes, in industry, and in agriculture. Describe how dams and water diversion projects are used to manage freshwater resources. Identify five ways that water can be conserved. Chapter 11

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Use and Management When a water supply is polluted or overused, everyone living downstream can be affected. A shortage of clean, fresh water is one of the world’s most pressing environmental problems. According to the World Health Organization, more than 1 billion people lack access to a clean, reliable source of fresh water. Chapter 11 Section 2 Water Use and Management

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Global Water Use There are three major uses for water: residential use, agricultural use, and industrial use. Chapter 11 Section 2 Water Use and Management

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Residential Water Use There are striking differences in residential water use throughout the world. For example, the average person in the United States uses about 300 L of water a day. But in India, the average person uses only 41 L of water everyday. In the U.S., only about half of residential water use is for activities inside the home, such as drinking and cooking. The remainder of the water used residentially is used for activities outside the home such as watering lawns. Chapter 11 Section 2 Water Use and Management

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Residential Water Use Chapter 11 Section 2 Water Use and Management

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Treatment Most water must first be made potable. Potable means suitable for drinking. Water treatment removes elements such as mercury, arsenic, and lead, which are poisonous to humans even in low concentrations. Chapter 11 Section 2 Water Use and Management

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Treatment A pathogen is a virus, microorganism, or other substance that causes disease. Pathogens are found in water contaminated by sewage or animal feces, but can be removed with water treatment. There are several methods of treating water to make it potable. A common method includes both physical and chemical treatment. Chapter 11 Section 2 Water Use and Management

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Drinking-Water Treatment Chapter 11 Section 2 Water Use and Management

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Industrial Water Use Industry accounts for 19 percent of water used in the world. Water is used to manufacture goods, to dispose of wastes, and to generate power. Chapter 11 Section 2 Water Use and Management

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Industrial Water Use Most of the water that is used in industry is used to cool power plants. The water that is returned is usually warmer than the source, but is generally clean and can be used again. Chapter 11 Section 2 Water Use and Management

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Agricultural Water Use Agriculture accounts for 67 percent of the water used in the world. Plants require a lot of water to grow, and as much as 80 percent of the water used in agriculture evaporates. Chapter 11 Section 2 Water Use and Management

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Irrigation Irrigation is a method of providing plants with water from sources other than direct precipitation. Crops are irrigated by shallow, water filled ditches or high-pressured overhead sprinklers. These methods are inefficient because nearly half the water evaporates and never reaches the plant roots. Chapter 11 Section 2 Water Use and Management

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Management Projects People often prefer to live in areas where the natural distribution of surface water is inadequate. Water management projects, such as dams, are designed to meet these needs. Water management projects can have various goals: –bringing in water to make a dry area habitable –creating a reservoir for drinking water –generating electric power Chapter 11 Section 2 Water Use and Management

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Dams and Reservoirs A dam is a structure that is built across a river to control a river’s flow. A reservoir is an artificial body of water that usually forms behind a dam. Water from a reservoir can be used for: –flood control –drinking water –irrigation –recreation –industry Chapter 11 Section 2 Water Use and Management

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Dams and Reservoirs But, interrupting a river’s flow can have consequences. For example, when the land behind a dam is flooded, people are displaced, and entire ecosystems can be destroyed. Fertile sediment also builds up behind a dam instead of enriching the land farther down the river, and farmland below may be less productive. Dam failure can be another problem. If a dam bursts, the people living along the river below may be killed. Chapter 11 Section 2 Water Use and Management

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Conservation As water sources become depleted, water becomes more expensive. This is because wells must be dug deeper, water must be piped greater distances, and polluted water must be cleaned up before it can be used. Water Conservation is one way that we can help ensure that everyone will have enough water at a reasonable price. Chapter 11 Section 2 Water Use and Management

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Conservation in Agriculture Use technologies to reduce evaporation, seepage, and runoff Drip irrigation systems : deliver small amounts of water directly to plant roots by using perforated tubing. Water is released to plants as needed Chapter 11 Section 2 Water Use and Management

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Conservation in Industry Recycling of cooling water and wastewater In an innovative program, Denver, Colorado pays small businesses to introduce water conservation measures. Chapter 11 Section 2 Water Use and Management

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Conservation at Home Chapter 11 Section 2 Water Use and Management

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Water Pollution Objectives Compare point-source pollution and nonpoint-source pollution. Classify water pollutants by five types. Explain why groundwater pollution is difficult to clean. Describe the major sources of ocean pollution, and explain the effects of pollution of ecosystems. Describe six major laws designed to improve water quality in the United States. Chapter 11

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Pollution Water pollution is the introduction into water of waste matter or chemicals. Water pollution comes from two types of sources: point and nonpoint sources. Chapter 11 Section 3 Water Pollution

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Point-Source Pollution Point-source pollution is pollution that comes from a specific site. For example: –A factory –A landfill –A leaking oil tanker Although point-source pollution can often be identified and traced to a source, enforcing cleanup is sometimes difficult. Chapter 11 Section 3 Water Pollution

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Nonpoint-Source Pollution Non-point source pollution is pollution that comes from many sources rather than from a single specific site. For example: –pollution from streets and storm sewers –runoff from lawns, crops –deposition from the air Controlling nonpoint-source pollution depends on public awareness of the effects of activities such as spraying lawn chemicals. Chapter 11 Section 3 Water Pollution

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Point and Nonpoint Sources of Pollution Chapter 11 Section 3 Water Pollution

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Principal Water Pollutants Chapter 11 Section 3 Water Pollution

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Wastewater Wastewater is water that contains wastes from homes (drains, toilets) or industry. At a wastewater treatment plant, water is filtered and treated to make the water clean enough to return to a river or lake. Pollutants in wastewater are usually biodegradable (soap, TP, sewage), but can contain some toxins (bad stuff poured down drain, street runoff) Chapter 11 Section 3 Water Pollution

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Sewage Sludge Sewage sludge: the solid material that remains after wastewater treatment (CHUNKS!). If the toxicity of sludge can be reduced to safe levels, it can be used as a fertilizer. Chapter 11 Section 3 Water Pollution

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Artificial Eutrophication When lakes and slow-moving streams contain an overabundance of nutrients, they are eutrophic. Eutrophication is a natural process: –Organic matter builds up; starts decomposing –O 2 levels decrease –Types of organisms that live in the water change over time. Chapter 11 Section 3 Water Pollution

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Artificial Eutrophication Sometimes inorganic plant nutrients, such as phosphorus and nitrogen, enter the water from sewage and fertilizer runoff (Artificial eutrophication). Major causes are fertilizer, and phosphates in some laundry detergents. Excess phosphorus causes rapid algae growth, suffocation of other organisms in water Chapter 11 Section 3 Water Pollution

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Thermal Pollution Thermal pollution is a temperature increase in a body of water that is caused by human activity Thermal pollution can occur when power plants and other industries use water in their cooling systems and then discharge the warm water into a lake or river. Thermal pollution can cause large fish kills if the discharged water is too warm for the fish to survive. Chapter 11 Section 3 Water Pollution

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Groundwater Pollution Pollutants usually enter groundwater when polluted surface water percolates down from the Earth’s surface. Common groundwater pollutants: Pesticides, chemical fertilizer, and petroleum products Other sources of pollution: septic tanks, unlined landfills, wastewater lagoons, leaking underground storage tanks Chapter 11 Section 3 Water Pollution

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cleaning Up Groundwater Pollution Groundwater pollution is one of the most challenging environmental problems in the world. Groundwater recharges very slowly; can take hundreds of years to recycle water Also, pollutants can cling to the materials that make up an aquifer Chapter 11 Section 3 Water Pollution

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ocean Pollution Pollutants can be dumped directly into the ocean by ships Biggest chunk (85%) of ocean pollution comes from activities on land, near the coasts. –Oil, toxic & medical wastes Sensitive coastal ecosystems, such as coral reefs, are the most affected by pollution. Chapter 11 Section 3 Water Pollution

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Oil Spills Each year, about 37 million gallons of oil from tanker accidents are spilled into the ocean. Such oil spills have dramatic effects, but they are responsible for only about 5 percent of oil pollution in the oceans. Chapter 11 Section 3 Water Pollution

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Oil Spills Chapter 11 Section 3 Water Pollution

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cleaning Up Water Pollution The Clean Water Act of 1972 was to designed to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.” Much progress has been made since the act was passed. –Increase in lakes fit for swimming –Stricter water quality standards Chapter 11 Section 3 Water Pollution

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cleaning Up Water Pollution Chapter 11 Section 3 Water Pollution