Freshwater resources 2006

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Freshwater resources 2006

  1. 1. Freshwater Resources Ms. Mills November 8, 2006
  2. 2. Water Supply and Demand <ul><li>5 ways that people use water are: </li></ul><ul><li>1. household purposes </li></ul><ul><li>2. industry </li></ul><ul><li>3. transportation </li></ul><ul><li>4. agriculture </li></ul><ul><li>5. recreation </li></ul>
  3. 3. Water Supply and Demand <ul><li>Household purposes </li></ul><ul><ul><ul><li>Flush toilet, wash hands, take shower/bath, drinking, cooking, washing clothes, cleaning, and the list can go on and on </li></ul></ul></ul>
  4. 4. Water Supply and Demand <ul><li>Agriculture </li></ul><ul><ul><ul><li>Irrigation – the process of supplying water to areas of land to make them suitable for growing crops. </li></ul></ul></ul><ul><ul><ul><li>In the United States, more water is used for irrigation than for any other single purpose. </li></ul></ul></ul>
  5. 5. Water Supply and Demand
  6. 6. Water Supply and Demand <ul><li>The practice of using less of a resource so that it will not be used up is Conservation. </li></ul><ul><li>Three ways to conserve water are to: </li></ul><ul><ul><ul><li>Recycle </li></ul></ul></ul><ul><ul><ul><li>Reuse </li></ul></ul></ul><ul><ul><ul><li>Reduce </li></ul></ul></ul>Three R's
  7. 7. Water Supply and Demand <ul><li>Two possible methods of obtaining freshwater in the future are: </li></ul><ul><ul><ul><li>Desalination </li></ul></ul></ul><ul><ul><ul><li>Melting Icebergs </li></ul></ul></ul><ul><li>Desalination = the process of removing salt from water </li></ul>
  8. 8. Water to Drink <ul><li>Water quality = measurement of the substances in water other than water molecules </li></ul><ul><li>Concentration = the amount of one substance in a certain volume of another substance </li></ul><ul><li>pH – measure of how acidic or basic a substance is </li></ul><ul><li>pH scale goes from 0 to 14 </li></ul><ul><li>Pure water is neutral at 7.0; acid <7, bases >7 </li></ul>
  9. 9. Water to Drink <ul><li>4 Things that can Affect the Quality of Water are: </li></ul><ul><ul><ul><li>Acidity </li></ul></ul></ul><ul><ul><ul><li>Disease-Causing Organisms </li></ul></ul></ul><ul><ul><ul><li>Chemicals </li></ul></ul></ul><ul><ul><ul><li>Hardness </li></ul></ul></ul><ul><li>Hardness – the combined levels of two minerals, calcium and magnesium, in a sample of water </li></ul><ul><li>Hard water has higher levels </li></ul><ul><li>Why does this matter?? </li></ul><ul><ul><li>Hard water does not form suds as easily as softer water </li></ul></ul>
  10. 10. Water to Drink <ul><li>Drinking-Water Treatment Process has 7 steps </li></ul><ul><ul><ul><li>First Filtration – filtered through screens to remove large particles (trash, fish, leaves) </li></ul></ul></ul><ul><ul><ul><li>Coagulation – Alum is added to cause sticky globs known as flocs. Mud and bacteria stick to these flocs. </li></ul></ul></ul><ul><ul><ul><li>Settling Basins – Water and flocs move onto a settling basin where the flocs settle out and sink to the bottom </li></ul></ul></ul>
  11. 11. Water to Drink <ul><li>Drinking-Water Treatment Cont </li></ul><ul><ul><ul><li>Second Filtration – water is then filtered through sand and gravel which can filter out some bacteria and chemicals </li></ul></ul></ul><ul><ul><ul><li>Chlorination – chlorine is added to kill remaining organisms </li></ul></ul></ul><ul><ul><ul><li>Aeration – Air is forced through the water which releases gases and rids it of unpleasant odors and tastes </li></ul></ul></ul><ul><ul><ul><li>Additional Treatment –fluoride, sodium, lime or other chemicals may be added to treat H 2 O </li></ul></ul></ul>
  12. 12. Water to Drink <ul><li>Treating Wastewater </li></ul><ul><ul><li>Wastewater and the different kinds of wastes in it is known as sewage . </li></ul></ul><ul><ul><li>Two ways that communities deal with wastewater are : septic systems and wastewater treatment plants. </li></ul></ul><ul><ul><li>Septic tank – an underground tank containing bacteria that treats wastewater as it passes through </li></ul></ul>
  13. 13. Water to Drink Septic Tank Wastewater Treatment Plant
  14. 14. Water to Drink <ul><li>Septic systems </li></ul><ul><ul><li>Inlet pipe from house </li></ul></ul><ul><ul><li>Bacteria in pipe begins to break down wastes </li></ul></ul><ul><ul><li>denser wastes settle to the bottom = sludge </li></ul></ul><ul><ul><li>Less dense wastes float to top = scum </li></ul></ul><ul><ul><li>Outlet pipe to leach field – water and broken down wastes go to leach field where they finish breaking down </li></ul></ul>
  15. 15. Water to Drink <ul><li>Wastewater Treatment Plants </li></ul><ul><ul><li>Preliminary Treatment – removes large trash </li></ul></ul><ul><ul><li>Primary Treatment – Water moves into settling tanks where trash settles out ( sludge ) </li></ul></ul><ul><ul><li>Secondary Treatment – Water is filtered through gravel, where bacteria on the gravel break down wastes. </li></ul></ul><ul><ul><li>Additional Treatment – Water is pumped into open pools where sunlight and air help purify it; chlorine may be added. Some water will rejoin the water cycle through evaporation. </li></ul></ul>
  16. 16. Freshwater Pollution <ul><li>Water Pollution – the addition of any substance that has a negative effect on water or the living things that depend on it. </li></ul><ul><li>Substances that cause water pollution are called pollutants . </li></ul>
  17. 17. Freshwater Pollution <ul><li>Sources of pollution are classified by how they enter a body of water. </li></ul><ul><li>Two ways: </li></ul><ul><ul><li>Directly enter (point source) </li></ul></ul><ul><ul><ul><li>Can be traced to a specific source </li></ul></ul></ul><ul><ul><li>Indirectly (non-point source) </li></ul></ul><ul><ul><ul><li>Widely spread and can’t be tied to a specific source of origin </li></ul></ul></ul>
  18. 18. Freshwater Pollution <ul><li>Pesticide- chemical intended to kill insects or other organisms that damage crops. </li></ul><ul><ul><li>DDT </li></ul></ul>
  19. 19. Freshwater Pollution <ul><li>Three major sources of water pollution are: </li></ul><ul><ul><li>Human wastes </li></ul></ul><ul><ul><li>Industrial wastes </li></ul></ul><ul><ul><li>Chemical runoff </li></ul></ul>
  20. 20. Freshwater Pollution <ul><li>Human wastes </li></ul><ul><ul><li>Sewage from cities </li></ul></ul><ul><ul><li>Sewage from rural areas </li></ul></ul><ul><li>Industrial Wastes </li></ul><ul><ul><li>Smoke and exhaust </li></ul></ul><ul><ul><li>Chemicals </li></ul></ul><ul><ul><ul><li>Smoke and exhaust in the air (nitrogen oxide and sulfur dioxide) can react with water in the atmosphere and lead to acid rain. </li></ul></ul></ul><ul><ul><ul><li>Acid rain is any rain or another precipitation that is more acidic than normal. </li></ul></ul></ul><ul><ul><li>Heat Pollution </li></ul></ul>
  21. 21. Freshwater Pollution <ul><li>Chemical Runoff </li></ul><ul><ul><li>Runoff from farms </li></ul></ul><ul><ul><li>Runoff from roads </li></ul></ul>
  22. 22. Freshwater Pollution <ul><li>There are two parts to the water pollution solution. </li></ul><ul><ul><li>Cleaning up old problems </li></ul></ul><ul><ul><li>Preventing new ones from occurring </li></ul></ul>
  23. 23. Droughts and Floods <ul><li>When an area experiences a long period of scarce rainfall, it is known as a drought. </li></ul><ul><ul><li>Caused by dry weather systems that remain in one place for weeks or months at a time </li></ul></ul><ul><ul><li>Can cause crop failure or even famine </li></ul></ul><ul><ul><li>In times of drought, people should conserve water </li></ul></ul>
  24. 24. Droughts and Floods <ul><li>The most dangerous weather-related events in the United States are floods! </li></ul><ul><li>Flash floods –sudden, violent flood that occurs within a few hours, or even minutes of a storm. </li></ul><ul><ul><ul><li>Usually due to large amounts of rain </li></ul></ul></ul><ul><ul><ul><li>May be caused by a dam breaking </li></ul></ul></ul>
  25. 25. Droughts and Floods <ul><li>Flood Precautions </li></ul><ul><ul><li>Advance warnings help reduce flood damage and loss of life. </li></ul></ul><ul><ul><li>Building dams are one method of flood control. </li></ul></ul><ul><ul><ul><li>A dam is a barrier across a river that may redirect the flow of a river to other channels. </li></ul></ul></ul><ul><ul><li>Natural defense against flooding </li></ul></ul><ul><ul><ul><li>Sediment (particles of rock and soil that are picked are build up and are carried along by forces) </li></ul></ul></ul><ul><ul><ul><li>Sediments can build up and form Levees (long ridges of sediment that naturally help keep rivers within their banks, can be reinforced with stone, sandbags and concrete) </li></ul></ul></ul>
  26. 26. Water Power <ul><li>Energy </li></ul><ul><ul><ul><li>Kinetic energy – the form of energy that an object has when it is moving </li></ul></ul></ul><ul><ul><ul><li>Potential Energy – energy that is stored and waiting to be used </li></ul></ul></ul><ul><li>Water and Energy </li></ul><ul><ul><ul><li>Hydroelectric power – Electricity produced by the kinetic energy of water moving over a waterfall or through a dam. </li></ul></ul></ul><ul><ul><ul><li>Hydroelectric power plants capture the kinetic energy of moving water and change it into electrical energy </li></ul></ul></ul>
  27. 27. Water Power <ul><li>Hydroelectric Power Plants can have advantages and disadvantages . </li></ul><ul><li>Advantages: </li></ul><ul><ul><ul><li>Clean, safe, efficient </li></ul></ul></ul><ul><ul><ul><li>Water is free </li></ul></ul></ul><ul><ul><ul><li>renewed by the water cycle </li></ul></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><ul><li>Flooding the land behind the dam can destroy wildlife habitats </li></ul></ul></ul><ul><ul><ul><li>Dams form a barrier and prevent fish from traveling to other parts of the river </li></ul></ul></ul><ul><ul><ul><li>Expensive to build dam </li></ul></ul></ul>
  28. 28. Water Power Initially, water has potential energy (sitting still in reservoir behind dam). Flows through penstocks (changes to kinetic energy) Turbine begins to turn (mechanical energy) Generator with magnet is turned on (electrical energy)
  29. 29. Water Power Blewett Falls Dam --Lilesville, NC
  30. 30. Freshwater Resources <ul><li>Have fun studying!!!!!! </li></ul>

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