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Freshwater Resources

Freshwater Resources. Water To Drink. Sources of Drinking Water. Your drinking water comes from either a public or private water supply. Sources could be: rivers, lakes reservoirs and aquifiers.

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Freshwater Resources

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  1. Freshwater Resources Water To Drink

  2. Sources of Drinking Water • Your drinking water comes from either a public or private water supply. • Sources could be: rivers, lakes reservoirs and aquifiers. • Most large communities maintain public water supplies. The community collects, treats, and distributes the water to its residents. • In smaller communities and rural areas, people reply on private wells that supply water for individual families.

  3. Treating Drinking Water • Water from both public and private supplies often needs some treatment to ensure that the water is safe and appealing to drink. • This can range from a simple filter on a well to a complex processes at public treatment plants.

  4. Drinking Water Treatment

  5. Appearance and Taste • Water Quality: is a measurement of the substances in water besides the water molecules.

  6. Acidity • The pH of water is a measurement of how acidic or basic it is. The scale ranges from 0 to 14. Pure water is neutral and has a pH of 7. The lower the pH the more acidic the water.

  7. Hardness of Water • The levels of calcium and magnesium in the water determines the hardness. • Hard water: Does not form suds well when mixed with soap. The minerals can clog pipes and machinery. • Soft water contains lower levels of these minerals. Therefore can suds up better.

  8. Treatment Plant • 1st Step is Filtration: The process of passing water through a series of screens that allows water through, but not larger objects.

  9. Second Step • Chemicals such as alum is added to cause sticky globs, called flocs, to form. • Other particles in the water stick to the flocs, a process called coagulation. • Heavy clumps sink to the bottom settling in basins.

  10. Last StepChorinate the water. • This is added to kill any disease causing microorganisms. • At this point the water is usually ready to be distributed to homes.

  11. Distribution of Water • From the treatment plant waste goes to a central pumping station. • There it is pumped into an underground network of steel or concrete pipes called water mains. • The water mains branch off into smaller pipes. • These feed into smaller copper or plastic pipes that carry water into houses and other buildings.

  12. Sewage • Water that goes down your drains. • This water can someday return as your drinking water. • Most communities treat wastewater to make it safe to return to the environment.

  13. Septic System • An underground tank containing bacteria that treat wastewater as it passes through. • Leach Fields: Area around the septic tank that the water filters through.

  14. Septic System

  15. Balancing Water Needs • A water shortage occurs when there is too little water or too great a demand in an area – or both. • Drought: Affects the supply of groundwater as well as surface water.

  16. Aquifer Overuse • When to much water is pumped out of an aquifer, the ground can sink or collapse. • When water is used up faster than the aquifer can be recharged, the aquifer is depleted, or emptied.

  17. Fresh Water for the Future • As the number of people in the world increases, so does the need for water. • Desalination: Obtaining fresh water from salt water. This is very expensive because of the energy and equipment it requires. • Icebergs: Tugboats could bring them where water is needed, but how would this affect the local weather?

  18. Desalination Plant

  19. Freshwater Pollution • Water Pollution: The addition of any substance that has a negative effect on water or the living things that depend on the water. • This can affect surface water, groundwater, and even rain. • It can result from both natural causes and human activities.

  20. Major Causes of Water Pollution • Human Wastes • Industrial wastes • Agricultural Chemicals • Runoff from roads

  21. Cleaning Up Polluted Water • Living things in lakes, streams, and wetlands filter out and break waste materials. • Plant roots filter larger particles from the water. • Wetlands are being built near coal mines to treat acidic mining runoff before it can reach the environment.

  22. Lakes and Streams

  23. Water As an Energy Resource • Hydroelectric power plants capture the kinetic energy of moving water and change it into electrical energy. • Hydroelectric power is clean, safe and efficient. Although building a dam is expensive, the water is free and is naturally renewed by the water cycle.

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