2. Chapter 14 Water-Overview of SurfaceWater (dams, water cycle, etc) NOT aquifer, pollutants, conservation

3. Chapter Overview Questions  Why is water so important, how much freshwater is available to us, and how much of it are we using?  What causes freshwater shortages, and what can be done about this problem?  What are the advantages and disadvantages of withdrawing groundwater?  What are the advantages and disadvantages of using dams and reservoirs to supply more water?

4. Chapter Overview Questions (cont’d)  What are the advantages and disadvantages of transferring large amounts of water from one place to another?  Can removing salt from seawater solve our water supply problems?  How can we waste less water?  How can we use the earth’s water more sustainably?  What causes flooding, and what can we do about it?

5. Core Case Study: Water Conflicts in the Middle East - A Preview of the Future  Many countries in the Middle East, which has one of the world’s highest population growth rates, face water shortages. Figure 14-1

6. Water Conflicts in the Middle East: A Preview of the Future  Most water in this dry region comes from the Nile, Jordan or Tigris rivers.  Countries are in disagreement as to who has water rights.  Currently, there are no cooperative agreements for use of 158 of the world’s 263 water basins that are shared by two or more countries.

7. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL  Water keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle.  Only about 0.02% of the earth’s water supply is available to us as liquid freshwater.

8. Types of Surface Water 1.Lentic- non-flowing a.Lake-larger, more diverse, often more oxygen b.Pond-smaller, less diverse, less oxygen. Light penetrates entire body of water 2.Lotic- flowing a.River- larger, more volume b.Stream- smaller, less volume COLD vs WARM Water and Oxygen

9. Cont. 3.Wetlands- terrestrial areas saturated part of the time with water. Can be fresh or saltwater. Wetland Services a.Biodiversity b.Water Trap (flood control) c.Carbon Dioxide Trap d.Pollutant Trap

10. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL  Some precipitation infiltrates the ground and is stored in soil and rock (groundwater).  Water that does not sink into the ground or evaporate into the air runs off (surface runoff) into bodies of water. –The land from which the surface water drains into a body of water is called its watershed or drainage basin.

11. Fig. 14-3, p. 308 Unconfined Aquifer Recharge Area Precipitation Evaporation and transpirationEvaporation Confined Recharge Area Runoff Flowing artesian well Recharge Unconfined Aquifer Stream Well requiring a pump Infiltration Water table Lake Infiltration Unconfined aquifer Confined aquifer Confining impermeable rock layer Less permeable material such as clay

12. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL  We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025.  About 70% of the water we withdraw from rivers, lakes, and aquifers is not returned to these sources.  Irrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%).

13. Water in the United States  Average precipitation (top) in relation to water-deficit regions and their proximity to metropolitan areas (bottom). Figure 14-4

14. Case Study: Freshwater Resources in the United States  17 western states by 2025 could face intense conflict over scarce water needed for urban growth, irrigation, recreation and wildlife. Figure 14-5

15. TOO LITTLE FRESHWATER  About 41% of the world’s population lives in river basins that do not have enough freshwater.  Many parts of the world are experiencing: –Rivers running dry. –Lakes and seas shrinking. –Falling water tables from overpumped aquifers.

16. Left off here 10-8-2014

17. Stress on the World’s River Basins  Comparison of the amount of water available with the amount used by humans. Figure 14-6

18. Case Study: Who Should Own and Manage Freshwater Resources  There is controversy over whether water supplies should be owned and managed by governments or by private corporations.  European-based water companies aim to control 70% of the U.S. water supply by buying up water companies and entering into agreements with cities to manage water supplies.

19. How Would You Vote?  Should private companies own or manage most of the world's water resources?

20. How Would You Vote?  Should private companies own or manage most of the world's water resources? –a. No. Democratically elected governments, which are accountable to the voters, should own and manage water resources. –b. Qualified yes. Governments should own the water, but expert private companies should manage it. –c. Depends. Each case must be decided independently. The record on private versus public ownership is mixed. –d. Yes. Private companies have more expertise and experience in managing water resources than most government bureaucrats.

21. TOO LITTLE FRESHWATER  Cities are outbidding farmers for water supplies from rivers and aquifers.  Countries are importing grain as a way to reduce their water use.  More crops are being used to produce biofuels.  Our water options are: –Get more water from aquifers and rivers, desalinate ocean water, waste less water.

22. USING DAMS AND RESERVOIRS TO SUPPLY MORE WATER  Large dams and reservoirs can produce cheap electricity, reduce downstream flooding, and provide year-round water for irrigating cropland.  But they also displace people and disrupt aquatic systems. (silt build-up, nutrient removal, temperature change, migration, habitat degradation and fragmentation)

23. Figure 14-13

24. Case Study: The Colorado Basin – an Overtapped Resource  The Colorado River has so many dams and withdrawals that it often does not reach the ocean. –14 major dams and reservoirs, and canals. –Water is mostly used in desert area of the U.S. –Provides electricity from hydroelectric plants for 30 million people (1/10 th of the U.S. population).

25. Case Study: The Colorado Basin – an Overtapped Resource  Lake Powell, is the second largest reservoir in the U.S.  It hosts one of the hydroelectric plants located on the Colorado River. Figure 14-15

26. The Colorado River Basin  The area drained by this basin is equal to more than one-twelfth of the land area of the lower 48 states. Figure 14-14

27. How Would You Vote? Do the advantages of large dams outweigh the disadvantages? –a. No. Large dams inflict extensive environmental damage and humans must learn to meet their needs without them. –b. Yes. Dams are critical in providing water and electricity for people, especially in developing countries.

28. Case Study: China’s Three Gorges Dam  There is a debate over whether the advantages of the world’s largest dam and reservoir will outweigh its disadvantages. –The dam is 1.4 miles long- 400 mile lake. –The electric output will be that of 18 large coal- burning or nuclear power plants. –It facilitates ship travel reducing transportation costs. –Dam displaced 1.3 million people. –Dam is built over seismic fault and already has small cracks.

29.  Will have cost 30 over billion dollars at completion  Lack of waste disposal  Cultural loss  Biodiversity loss  Ecosystem issues

30. http://www.nytimes.com/2011/05/20/world/asi a/20gorges.html?scp=3&sq=three+gorges+da m&st=nyt http://www.nytimes.com/2011/05/20/world/asi a/20gorges.html?scp=3&sq=three+gorges+da m&st=nyt

31. Dam Removal  Some dams are being removed for ecological reasons and because they have outlived their usefulness. –In 1998 the U.S. Army Corps of Engineers announced that it would no longer build large dams and diversion projects in the U.S. –The Federal Energy Regulatory Commission has approved the removal of nearly 500 dams. –Removing dams can reestablish ecosystems, but can also re-release toxicants into the environment.

32. TRANSFERRING WATER FROM ONE PLACE TO ANOTHER  Transferring water can make unproductive areas more productive but can cause environmental harm. –Promotes investment, jobs and strong economy. –It encourages unsustainable use of water in areas water is not naturally supplied.

33. Case Study: The California Experience  A massive transfer of water from water-rich northern California to water-poor southern California is controversial. Figure 14-16

34. Case Study: The Aral Sea Disaster  The Aral Sea was once the world’s fourth largest freshwater lake. Figure 14-17

35.  http://www.orexca.com/aral_sea.shtml http://www.orexca.com/aral_sea.shtml

36. p://www.mapsofworld.com/tajikistan/shrinking- aral-sea-map.html p://www.mapsofworld.com/tajikistan/shrinking- aral-sea-map.html

37. Case Study: The Aral Sea Disaster  Diverting water from the Aral Sea and its two feeder rivers mostly for irrigation has created a major ecological, economic, and health disaster. –About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared. –Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.

38. Flooding

39. TOO MUCH WATER  Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.  Floodplains, which usually include highly productive wetlands, help provide natural flood and erosion control, maintain high water quality, and recharge groundwater.  To minimize floods, rivers have been narrowed with levees and walls, and dammed to store water.

40. TOO MUCH WATER  Comparison of St. Louis, Missouri under normal conditions (1988) and after severe flooding (1993). Figure 14-22