1. Chapter 14 Water

2. 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?

3. 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?

4. Water Stats  Water and Urbanization -The world population is predicted to grow from 6.9 billion in 2010 to 8.3 billion in 2030 and to 9.1 billion in 2050. At the same time, urban population is projected to increase by 2.9 billion, to a total of 6.3 billion in 2050. Sources: WWDR 2012 -Today, one in two people on the planet live in a city. Source: UNESCO -93% of the urbanization occurs in poor or developing countries, and nearly 40% of the world's urban expansion is growing slums. Source: UN-HABITAT 'State of the World's Cities 2010-2011' report -Slums are projected to grow by 27 million people per year. In Africa and Asia, the urban population will double between 2000 and 2030. 5 million people are joining the urban population in the developing world each month. Source: UN-HABITAT -827.6 million people live in slums, often lacking adequate drinking water and sanitation services. Source: UN-HABITAT -One of four city residents worldwide, 194 million in total, lives without access to improved sanitation facilities. Source: WHO

5. Continued  Water and Climate Change -There is evidence that the global climate is changing. A global temperature increase of 3-4°C could cause changed run-off patterns and glacial melt will force an additional 1.8 billion people to live in a water scarce environment by 2080. Source: UNDP: Human Development Report, 2007/2008 -Climate change is predicted to have a whole range of impacts on water resources. Variation in temperature and rainfall may affect water availability, increase the frequency and severity of floods and droughts, and disrupt ecosystems that maintain water quality. Source: Intergovernmental Panel on Climate Change (IPCC) -By 2050, rising populations in flood-prone lands, climate change, deforestation, loss of wetlands and rising sea levels are expected to increase the number of people vulnerable to flood disaster to 2 billion. Source: WWDR, 2012

6. Water Resources Stats  The total volume of water on Earth is about 1.4 billion km3. The volume of freshwater resources is around 35 million km3, or about 2.5 percent of the total volume. Source: United Nations Environment Programme (UNEP) Of these freshwater resources, about 24 million km3 or 70 percent is in the form of ice and permanent snow cover in mountainous regions, the Antarctic and Arctic regions. Source: UNEP Around 30 percent of the world's freshwater is stored underground in the form of groundwater (shallow and deep groundwater basins up to 2 000 metres, soil moisture, swamp water and permafrost). This constitutes about 97 percent of all the freshwater that is potentially available for human use. Source: UNEP

7. Water Resources

8. Water Use -Water use has been growing at more than twice the rate of population increase in the last century. Source: Food and Agriculture Organization of the United Nations (FAO) and UN- Water -How the world uses freshwater: about 70 percent for irrigation about 20 percent for industry about 10 percent for domestic use Source: World Water Assessment Programme (WWAP) -70% of the blue water withdrawals at global level go to irrigation. Irrigated agriculture represents 20% of the total cultivated land but contributes 40% of the total food produced worldwide. Source: FAO, 2012 -Part of the current pressure on water resources comes from increasing demands for animal feed. Meat production requires 8-10 times more water than cereal production. Source: WWDR, 2012

9. Water Use Continued -Water withdrawals are predicted to increase by 50 percent by 2025 in developing countries, and 18 per cent in developed countries. Source: Global Environment Outlook: environment for development (GEO-4) -Over 1.4 billion people currently live in river basins where the use of water exceeds minimum recharge levels, leading to the desiccation of rivers and depletion of groundwater. Source: Human Development Report 2006 -In 60 percent of European cities with more than 100,000 people, groundwater is being used at a faster rate than it can be replenished. Source: World Business Counicl For Sustainable Development (WBCSD)

10. Water Use

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

12. 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 agreements for use of 158 of the world’s 263 water basins that are shared by two or more countries.

13. 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 water (hydrologic) cycle.

14. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL  Comparison of population sizes and shares of the world’s freshwater among the continents. Figure 14-2

15. 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. watershed or drainage basin: where surface water drains into a body of water watershed or drainage basin: where surface water drains into a body of water

16. 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

17. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL  About 70% of the water we take 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%).

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

19. Fig. 14-5, p. 310 Wash. Montana Oregon N.D. Idaho Wyoming S.D. NevadaNeb. Utah Colo. Kansas California Oak. N.M. Texas Highly likely conflict potential Moderate conflict potential Unmet rural water needs Substantial conflict potential

20. 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 (dessication) Rivers running dry (dessication) Lakes and seas shrinking. Lakes and seas shrinking.

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

22. TOO LITTLE FRESHWATER  Cities are outbidding farmers for water supplies from rivers and aquifers.  More crops are being used to produce biofuels.  Our water options are: Get more water from aquifers Get more water from aquifers Desalinate ocean water Desalinate ocean water Waste less water Waste less water

23. WITHDRAWING GROUNDWATER TO INCREASE SUPPLIES  Most aquifers are renewable resources unless water is removed faster than it is replenished or if they are contaminated.  Groundwater depletion is a growing problem mostly from irrigation. At least 1/4 of the farms in India are being irrigated from over-used aquifers. At least 1/4 of the farms in India are being irrigated from over-used aquifers.

24. Groundwater Depletion: A Growing Problem  The Ogallala, the world’s largest aquifer, is most of the red area in the center (Midwest).  Water being used 8x faster than it can be recharged  Areas of greatest aquifer depletion from groundwater occur in the continental U.S. Figure 14-8

25. Ogallala Aquifer  http://www.youtube.com/watch?v=XXFsS94H F08 http://www.youtube.com/watch?v=XXFsS94H F08 http://www.youtube.com/watch?v=XXFsS94H F08

26. Other Effects of Groundwater Overpumping  Groundwater overpumping can cause land to sink, and contaminate freshwater aquifers near coastal areas with saltwater. Figure 14-11

27. Other Effects of Groundwater Overpumping  Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater. Figure 14-10

28. Fig. 14-12, p. 316 Solutions Groundwater Depletion PreventionControl Waste less water Raise price of water to discourage waste Subsidize water conservation Ban new wells in aquifers near surface waters Tax water pumped from wells near surface waters Buy and retire groundwater withdrawal rights in critical areas Do not grow water- intensive crops in dry areas Set and enforce minimum stream flow levels

29. USING DAMS AND RESERVOIRS TO SUPPLY MORE WATER  Large dams and reservoirs can: produce cheap electricity reduce downstream flooding provide year-round water for irrigating cropland …but they also displace people and disrupt aquatic systems.

30. Fig. 14-13a, p. 317 Provides water for year-round irrigation of cropland Flooded land destroys forests or cropland and displaces people Large losses of water through evaporation Provides water for drinking Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Risk of failure and devastating downstream flooding Can produce cheap electricity (hydropower) Downstream flooding is reduced Migration and spawning of some fish are disrupted Advantages Disadvantages

31. Fig. 14-13b, p. 317 Powerlines Reservoir Dam Powerhouse Intake Turbine

32. 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. 14 major dams and reservoirs, and canals. Water is mostly used in desert area of the U.S. 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). Provides electricity from hydroelectric plants for 30 million people (1/10 th of the U.S. population).

33. Case Study: The Colorado Basin – an Overtapped Resource  Lake Powell, is the second largest reservoir in the U.S (Lake Mead is largest)  It has one of the hydroelectric plants located on the Colorado River. Figure 14-15

34. The Colorado River Basin  The area drained by this basin is equal to more than 1/12 of the land area of the lower 48 states. Figure 14-14

35. 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 electric output will be that of 18 large coal- burning or nuclear power plants. The electric output will be that of 18 large coal- burning or nuclear power plants. It will facilitate ship travel reducing transportation costs. It will facilitate ship travel reducing transportation costs. Dam will displace 1.2 million people. Dam will displace 1.2 million people. Dam is built over a fault and already has small cracks. Dam is built over a fault and already has small cracks. Construction started in 1994 and finished in 2008 Construction started in 1994 and finished in 2008

36. 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. 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. The Federal Energy Regulatory Commission has approved the removal of nearly 500 dams. Removing dams can reestablish ecosystems, but can also re-release toxins into the environment. Removing dams can reestablish ecosystems, but can also re-release toxins into the environment.

37. 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. Promotes investment, jobs and strong economy. It encourages unsustainable use of water in areas where water is not naturally supplied. It encourages unsustainable use of water in areas where water is not naturally supplied.

38. 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

39. DESALTING SEAWATER, SEEDING CLOUDS, AND TOWING ICEBERGS AND GIANT BAGGIES  Removing salt from seawater by current methods is expensive and produces large amounts of salty wastewater that must be disposed of safely. Distillation: heating saltwater until it evaporates, leaves behind water Distillation: heating saltwater until it evaporates, leaves behind water Reverse osmosis: uses high pressure to force saltwater through a membrane filter. Reverse osmosis: uses high pressure to force saltwater through a membrane filter.

40. Continued…  Seeding clouds with tiny particles of chemicals to increase rainfall, towing icebergs or huge bags filled with freshwater to dry coastal areas have all been proposed but are unlikely to provide significant amounts of freshwater.

41. INCREASING WATER SUPPLIES BY WASTING LESS WATER  We waste about 2/3 of the water we use, but we could cut this waste to 15%. 65-70% of the water people use is lost through evaporation, leaks, etc. 65-70% of the water people use is lost through evaporation, leaks, etc. The lack of government incentive for improving the efficiency of water use contributes to water waste. The lack of government incentive for improving the efficiency of water use contributes to water waste.

42. INCREASING WATER SUPPLIES BY WASTING LESS WATER  60% of the world’s irrigation water is currently wasted, but improved irrigation techniques could cut this waste to 5-20%.  Low pressure sprinklers spray water directly onto crop. It allows 80% of water to reach crop. It allows 80% of water to reach crop. Has reduced depletion of Ogallala aquifer in Texas by 30%. Has reduced depletion of Ogallala aquifer in Texas by 30%.

43. Fig. 14-18, p. 325 Center pivot Drip irrigation Gravity flow (efficiency 60% and 80% with surge valves) Above- or below- ground pipes or tubes deliver water to individual plant roots. Water usually comes from an aqueduct system or a nearby river. (efficiency 90–95%) (efficiency 80%–95%) Water usually pumped from underground and sprayed from mobile boom with sprinklers.

44. Fig. 14-19, p. 326 Solutions Reducing Irrigation Water Waste Line canals bringing water to irrigation ditches Level fields with lasers Irrigate at night to reduce evaporation Monitor soil moisture to add water only when necessary Polyculture Organic farming Don't grow water-thirsty crops in dry areas Grow water-efficient crops using drought resistant and salt-tolerant crop varieties Irrigate with treated urban waste water Import water-intensive crops and meat

45. Solutions: Getting More Water for Irrigation in Developing Countries – The Low-Tech Approach  Many poor farmers in developing countries use low-tech methods to pump groundwater and make more efficient use of rainfall. Figure 14-20

46. Fig. 14-21, p. 327 Solutions Reducing Water Waste Redesign manufacturing processes Repair leaking underground pipes Landscape yards with plants that require little water Use drip irrigation Fix water leaks Use water meters Raise water prices Use waterless composting toilets Require water conservation in water- short cities Use water-saving toilets, showerheads, and front loading clothes washers Collect and reuse household water to irrigate lawns and nonedible plants Purify and reuse water for houses, apartments, and office buildings Don't waste energy

47. Solutions: Using Less Water to Remove Industrial and Household Wastes  We can mimic the way nature deals with wastes instead of using large amounts of high-quality water to wash away and dilute industrial and animal wastes. Use nutrients in wastewater before treatment as soil fertilizer. Use nutrients in wastewater before treatment as soil fertilizer. Use waterless and low flow toilets and low flow showerheads. Use waterless and low flow toilets and low flow showerheads.

48. TOO MUCH WATER  Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding.  Floodplains, (which 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.

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

50. Fig. 14-24, p. 331 Solutions Reducing Flood Damage PreventionControl Preserve forests on watersheds Strengthen and deepen streams (channelization) Preserve and restore wetlands in floodplains Tax all development on floodplains Build levees or floodwalls along streams Use floodplains primarily for recharging aquifers, sustainable agriculture and forestry, and recreation Build dams

51. SOLUTIONS: USING WATER MORE SUSTAINABLY  We can use water more sustainably by: Cutting waste Raising water prices Preserving forests and wetlands in water basins Slowing population growth. Figure 14-25

52. Fig. 14-25, p. 333 What Can You Do? Water Use and Waste Use water-saving toilets, showerheads, and faucet aerators. Shower instead of taking baths, and take short showers. Stop water leaks. Turn off sink faucets while brushing teeth, shaving, or washing. Flush toilets only when necessary. Wash only full loads of clothes or use the lowest water-level for smaller loads. Use recycled (gray) water for lawn, gardens, house plants, car washing. Wash a car from a bucket of soapy water, and use the hose for rinsing only. If you use a commercial car wash, try to find one that recycles its water. Replace your lawn with native plants that need little if any watering and decorative gravel or rocks. Water lawns and gardens in the early morning or evening. Sweep or blow off driveways instead of hosing off with water. Use drip irrigation and mulch for gardens and flowerbeds.