Chapter 14

1. Chapter 14 Water

2. 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

3. 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 upstream are building dams and drawing more water…leaving little for downstream countries • Countries are in disagreement as to who has water rights. • War could easily erupt in this volatile part of the world

4. Water Conflicts in the Middle East: A Preview of the Future • 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. • Emerging water shortages in many parts of the world – one of the most serious environmental problems

5. WATER’S IMPORTANCE, AVAILABILITY, AND RENEWAL • Necessary for life • Moderates climate, • Sculpts the land, • Removes and dilutes wastes and pollutants, • Moves continually through the hydrologic cycle. • Only about 0.02% of the earth’s water supply is available to us as liquid freshwater.

6. Water • One of our most poorly managed resource • We waste & pollute it • No substitute • Lack of safe water & sanitation is leading cause of illness in world • Water quality is worsening

7. Water By The Numbers • Oceans: 97% • Glaciers / polar ices caps: 1.8% • Groundwater: 0.9% • Other land surface water (rivers, lakes): 0.017% • 20% of all surface freshwater is in Lake Baikal, Russia. • The Ogallala Aquifer is the largest groundwater reserve. • The Middle East has the lowest amount of naturally available freshwater and uses desalination for their water supply. Lake Bikal is the most voluminous freshwater lake in the world. The Ogallala Aquifer is located in the central plains of the US because of watershed properties

8. Atmospheric water 0.04% Rivers 2% Fresh water 3% Surface water 0.3% Ground water 22.46% Swamps 11% Seawater 97 % Lakes 87% Ice caps and glaciers 77.2% Earth’s total water Surface water Fresh water Fresh Water Resources • Most of the 71% of Earth’s water, more than 1.3 billion cubic kilometers, is contained in the oceans. Only 35 million cubic kilometers is fresh water. • Only a tiny amount of the water on Earth is accessible and usable to humans because the ice caps/sheets/ glaciers are the majority of freshwater and are not readily available for use.

9. Surface Water • Examples – streams, rivers, and lakes • Source – precipitation • Watershed – Ex. small streams  larger streams  rivers  sea

10. Groundwater • Aquifers–porous rock w/ water flowing through • Water Table – the level of earth’s land crust to which the aquifer is filled • Renewability – the circulation rate of groundwater is slow (300 to 4,600 years).

11. Water Usage • Agriculture – watering crops • Industry – coolant (power plant) • Domestic and Municipal – drinking, sewage, bathwater, dishwater & laundry

12. The Demand for Water • Humans intervene in the water cycle by utilizing the resource for their own needs. • Water is used for consumption, municipal use, in agriculture, in power generation, and for industrial manufacturing. • Industry is the greatest withdrawer of water but some of this is returned. Agriculture is the greatest water consumer. • Using water often results in its contamination. The supply of potable (drinkable) water is one of the most pressing of the world’s problems. Hydroelectric power generation… Irrigation… Washing, drinking, bathing…

13. Water in many developing nations is difficult to come by, and treatment may be nonexistent. In developed nations, potable water is abundant and treatment is regulated. Potable Water • Potable water (water suitable to drink) is a rare commodity in large parts of the world. • Access to potable water is limited by: • ease of distribution, level of water treatment (e.g. sanitation), & amount of available water resources (eg rivers) • Countries must deal with problems of removing water borne diseases and dissolved toxins. • Once treated, distribution and storage of water becomes important. • In many countries, distribution of water is difficult and storage of large amounts almost impossible. Photo: Bob Metcalf

14. Comparison of population sizes and shares of the world’s freshwater among the continents. Figure 14-2

15. Ogallala Aquifer A vast water-table aquifer located beneath the Great Plains in the US. It is extensively used for irrigation. At current usage rates it may be depleted by 2020. North American Great Lakes The largest group of freshwater lakes on Earth, containing 22% of the world's fresh surface water. Amazon River Accounts for 20% of the world's total river flow and drains 40% of South America. Brazil has the largest supply of freshwater in the world. Mississippi River Drains most of the area between the Rocky Mountains and the Appalachians. A series of locks and dams provide for barge traffic. Global Water Reserves

16. Volga River With its many tributaries, drains an area of about 1.35 million km2 in the most heavily populated part of Russia. High levels of chemical pollution currently give cause for environmental concern. Lake Baikal Is the second most voluminous lake in the world. Contains 20% of the world’s freshwater Yangtze River Flows 6300 km East China Sea. The Yangtze is subject to extensive flooding, which is only partly controlled by the Three Gorges Dam. It is also heavily polluted. Congo River Is the largest river in Western Central Africa with the second-largest flow in the world. It drains an extensive area of rainforest. Murray-Darling Basin Drains one-seventh of the Australian land mass. Over 70% of Australia's irrigation resources are concentrated there. Ganges Basin Central to the agricultural economy of India. A recent UN report indicates the glaciers feeding the Ganges may disappear by 2030, leaving it as a seasonal system fed by the monsoon rains. Global Water Reserves

17. An automobile: 380,000 liters of water Fresh Water Use • Intensive agriculture uses large amounts of water, 69% of the freshwater. • Improved irrigation techniques can reduce the amount required. • Every year huge quantities of water as transported to irrigate crops. • Industrial water use increases along with the human population, using about 22% of freshwater. • The cooling of power plants and the processing of almost all commercial goods requires the use the water. • Manufacturing and production processes are usually water intensive. Some everyday items use surprisingly large amounts of water in their production. Irrigation accounts for 69% Industrial treatment uses 22%

18. 454 g of grain-fed beef: 3,000 liters of water The cotton in a pair of jeans: 6,800 liters of water Municipal Water Use • Cities and residences use only 8% of the freshwater. Nearly half of the municipal water in the US is used to flush toilets or water lawns. • Another 20-35% is lost in water leaks. • Large savings can be made by improving the efficiency of water use. • Treatment of waste water is a major issue. Municipal supply is about 8%

19. Agricultural Water Use Domestic Water Use Industrial Water Use Cubic meters per person per year Cubic meters per person per year Cubic meters per person per year Water Use: America Source: Worldwater.org

20. Agricultural Water Use Domestic Water Use Industrial Water Use Water Use: Africa Cubic meters per person per year Cubic meters per person per year Cubic meters per person per year Source: Worldwater.org

21. Agricultural Water Use Industrial Water Use Domestic Water Use Water Use: Asia Cubic meters per person per year Cubic meters per person per year Cubic meters per person per year Source: Worldwater.org

22. Agricultural Water Use Domestic Water Use Industrial Water Use Water Use: Europe Cubic meters per person per year Cubic meters per person per year Cubic meters per person per year Source: Worldwater.org

23. Agricultural Water Use Domestic Water Use Industrial Water Use Water Use: Oceania Cubic meters per person per year Cubic meters per person per year Cubic meters per person per year Source: Worldwater.org

24. 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.

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

26. 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%).

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

28. Average annual precipitation (centimeters) Less than 41 81–122 41–81 More than 122 Fig. 14-4a, p. 309

29. Acute shortage Shortage Adequate supply Metropolitan regions with population greater than 1 million Fig. 14-4b, p. 309

30. 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

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

32. 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.

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

34. 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.

35. 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.

36. 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 one-fourth of the farms in India are being irrigated from overpumped aquifers.

37. Trade-Offs Withdrawing Groundwater Advantages Disadvantages Useful for drinking and irrigation Aquifer depletion from overpumping Sinking of land (subsidence) from overpumping Available year-round Exists almost everywhere Polluted aquifers for decades or centuries Renewable if not overpumped or contaminated Saltwater intrusion into drinking water supplies near coastal areas Reduced water flows into surface waters No evaporation losses Increased cost and contamination from deeper wells Cheaper to extract than most surface waters Fig. 14-7, p. 313

38. Damming and diverting rivers lowers the availability of water downstream and stops annual floods that replace soil nutrients. Dams, locks and other obstacles make it very difficult for migratory fish to find their way to breeding grounds. Irrigation can move move millions of liters of water from rivers and aquifers, affecting land down stream. Human Effects • Most water used by humans comes from rivers, lakes, & aquifers. • Damming rivers for electricity affects water flow downstream as seen in the James Bay project in Quebec with over 600 dams blocking 19 rivers. • Irrigation and diversions for drinking water displace vast amounts of the water for these resource stores. • Pollution from fertilizers, waste, an sewage can have paralyzing effects on rivers, lakes, and oceans. • These actions can have dramatic effects on the habitats and can cause loss of biodiversity.

39. Rivers as Highways • The major rivers of the worlds provide water for irrigation and drinking and enable the transport of large amounts of freight especially when dammed. • Huge barges moved by tugboats are used on many rivers and lakes of developed countries. • However there are many negative environmental effects. • Some rivers such as the Yangtze are so polluted and congested with ships that little can live in them. • The Yangtze River Dolphin was last seen in 2002 and has since been declared functionally extinct. It is the first cetacean extinction directly attributable to human interference. Mississippi River, USA Photo: Ryu Cheoi Creative CommonsAttribution ShareAlike 3.0 Yangtze River, China

40. Groundwater Depletion: A Growing Problem • The Ogallala, the world’s largest aquifer, is most of the red area in the center (Midwest). • Areas of greatest aquifer depletion from groundwater overdraft in the continental U.S. Figure 14-8

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

42. Major irrigation well Well contaminated with saltwater Water table Sea level Fresh groundwater aquifer Saltwater Seafloor Interface Saltwater intrusion Interface Normal interface Fig. 14-11, p. 315

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

44. Groundwater Pumping in Saudi Arabia (1986 – 2004) • Irrigation systems from the nonrenewable aquifer appear as green dots. Brown dots are wells that have gone dry. Figure 14-9

45. Solutions Groundwater Depletion Prevention Control Raise price of water to discourage waste Waste less water 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 Set and enforce minimum stream flow levels Do not grow water-intensive crops in dry areas Fig. 14-12, p. 316

46. 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.

47. Dams and Reservoirs • Benefits: Hydroelectric power; provides water to towns; recreation; controls floods downstream • Problems: Reduces downstream flow; prevents water from reaching the sea (Colorado River) devastates fish life; reduces biodiversity.

48. Figure 14-13

49. 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 Fig. 14-13a, p. 317

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