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Water Resources

Water Resources. Chapter 13. Core Case Study: Water Conflicts in the Middle East: A Preview of the Future. Water shortages in the Middle East: hydrological poverty Nile River Jordan Basin Tigris and Euphrates Rivers Peacefully solving the problems. 13-1 Will We Have Enough Usable Water?.

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Water Resources

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  1. Water Resources Chapter 13

  2. Core Case Study: Water Conflicts in the Middle East: A Preview of the Future • Water shortages in the Middle East: hydrological poverty • Nile River • Jordan Basin • Tigris and Euphrates Rivers • Peacefully solving the problems

  3. 13-1 Will We Have Enough Usable Water? 1) Freshwater is irreplaceable a) Water covers about 71% of the surface b) Water makes up about 60% of our body and it’s properties affect life on earth c) You can only survive a few days without it d) It takes huge amounts to provide for our daily needs e) Water also sculpts the surface, moderates climate, and removes wastes and pollutants f) Water is one of our most poorly managed resources

  4. 13-1 Will We Have Enough Usable Water? g) We also charge too little for making it available, which encourages greater waste and pollution h) Access to water is a global health issue, lack of access to clean water & sanitation is the largest cause of illness i) WHO estimated that 1.6 million people die from waterborne diseases j) It is also an economic issue, women's &children’s issue, national and global security issue and an environmental issue

  5. Fig. 13-3, p. 319

  6. 13-1 Will We Have Enough Usable Water? 2) Most of the FW is not available a) Only about .024% of water is available b) Rest is salt water, frozen or very deep underground c) Hydrologic cycle: Water cycle works well, unless it is overloaded d) We also interfere with the cycle by destroying wetlands, cutting down forest & global warming e) We actually have plenty of water, but it is not evenly distributed

  7. 13-1 Will We Have Enough Usable Water? 3) Where we get water a) Groundwater: water in the spaces under ground b) Zone of saturation: spaces completely filled with water c) Water table: the upper level of the zone d) Aquifer: underground caverns & porous layers where groundwater flows e) Natural recharge: precipitation that percolates downward into aquifers

  8. 13-1 Will We Have Enough Usable Water? f) Lateral recharge: water flowing in from the side from rivers g) Recharge is very slow and paving or building over areas has decreased the process h) Nonrenewable aquifer: get very little recharge and are found deep underground and formed tens of thousands of years ago. i) Water mining: process removing water from deep aquifers j) Surface water: rivers, lakes, streams, etc.

  9. 13-1 Will We Have Enough Usable Water? k) Surface runoff: water that doesn’t move into aquifers l) Water shed (drainage basin) land area where runoff supplies a river or other body of water m) Most groundwater eventually flows into rivers, lakes estuaries or wetlands 4) We use a large portion of the reliable runoff a) Reliable runoff: water that we can generally count on as a source of freshwater each year.

  10. 13-1 Will We Have Enough Usable Water? b) About 2/3 of annual runoff is lost by floods c) We use about 34% of the world’s reliable runoff d) By 2025 we could be using 70% and 90% if per capita withdrawal continues increasing at the current rate e) Uses 70% irrigation 20% industrial 10% residential d) Affluence increases the amount of water used

  11. Fig. 13-A, p. 321

  12. Case Study: Freshwater Resources in the United States (pg 317) • More than enough renewable freshwater, unevenly distributed • Effect of • Floods • Pollution • Drought • 2007: U.S. Geological Survey projection • Water hotspots

  13. Fig. 13-5, p. 322

  14. 13-1 Will We Have Enough Usable Water? 5) Water shortages will grow a) Main factors leading to scarcity 1. dry climate 2. drought 3. too many people using a reliable supply 4. wasteful use of water b) More than 30 countries face water scarcity, 60 are likely to have water stress Fig 13-6 page 319 shows current degree of stress

  15. Fig. 13-6, p. 323

  16. 13-1 Will We Have Enough Usable Water? c) Poor bear the brunt of water shortages d) Un reported 1.1 billion people (1-6) lacked regular access to enough clean water e) 2.6 billion lacked access to have basic sanitation 6) Long term drought is increasing a) Caused by lack of normal rainfall & diminished groundwater due to falling water tables b) Harmful environmental effects: dries soil, reduces stream flow, decreases tree growth & biomass, lowers NPP, reduces crop yield, causes a shift in biomes

  17. 13-1 Will We Have Enough Usable Water? c) The big dry: About 30% of the earth’s land experiences severe drought, by 2059 as much as 45% could experience extreme drought d) Since 99, much of the US has experienced severe drought e) There has been a drop in crop productivity and increased in arguments of water supplies between farmers and urban areas 7) Competition in water short areas a) Farmers are losing the battle for water

  18. 13-1 Will We Have Enough Usable Water? b) Some areas are reducing irrigation water needs by importing grain c) Water shortages are causing an increase in the competition in the world’s grain markets d) Using crops for biofuel adds to the competition e) Bottom line: farmers, cities and car owners are increasingly competing for access to the world’s grain and water supplies, which in turn can degrade some of the natural capital that provides these resources (page 320)

  19. 13-1 Will We Have Enough Usable Water? 7) Who should own & manage FW Resources a) Most believe that everyone should have access to water, but who will pay to make it available? b) Most water resources are owned by governments and managed as publicly owned resources for their citizens. c) Some governments are hiring private companies to manage it or selling their water resources d) 2French Companies (Veolia & Suez) are trying to buy or manage as much of the water as they can

  20. 13-1 Will We Have Enough Usable Water? e) 85% of Americans get their water from publicly owned utilities, but within 10 yrs these companies plan to control 70% of the water supply in the US. f) The public-private partnership has had mixed results (page 320) g) Many oppose full privatization of water because they believe that water is a public resource too important to be left in private hands h) It is difficult and costly to regain control, private companies encourage waste, poor may lose access

  21. 13-2 Is Extracting Groundwater the Answer? 1) Water tables fall a) Most aquifers are renewable and provide drinking water for about ½ of the world b) In the US it provides most of the rural areas, 1/5 of urban areas and 37% of irrigation c) Figure 13-7 Page 321

  22. 13-2 Is Extracting Groundwater the Answer? d) The world’s 3 larges grain producers and several other countries are overpumping many of the aquifers e) More than ½ a billion people are being fed by grain produced through the unsustainable use of groundwater and the number is expected to grown f) Inexpensive tubewells has accelerated overpumping g) As the tables fall, farmers drill deeper wells, buy larger pumps and use more energy to pump water eventually depleting the aquifer

  23. Fig. 13-12, p. 327

  24. 13-2 Is Extracting Groundwater the Answer? Pg 322 h) Hydrologist estimate that because of aquifer depletion most irrigated agriculture in Saudi Arabia may disappear within 1-2 decades

  25. Case Study: Aquifer Depletion in the United States • Ogallala aquifer: largest known aquifer • Irrigates the Great Plains • Water table lowered more than 30m • cost of high pumping has eliminated some of the farmers • Government subsidies to continue farming deplete the aquifer further • Biodiversity threatened in some areas • California Central Valley: serious water depletion

  26. 2) Groundwater Overpumping Has Other Harmful Effects a) Limits future food production b) Increases the gap between rich and poor: poor farmers can’t afford pumping, lose land and move to overpopulated cities c) Land subsidence: occurs with sand and rock in aquifers collapse, prevents recharge, causes buildings and roads to collapse d) Sinkholes: appear suddenly and unexpectedly e) Can cause saltwater intrusion into aquifers

  27. Science Focus: Are Deep Aquifers the Answer? (page 324) • Locate the deep aquifers; determine if they contain freshwater or saline water • Major concerns • Geological and ecological impact of pumping water from them • Flow beneath more than one country • Who has rights to it?

  28. 13-3 Is Building More Dams the Answer? 1) Advantages and Disadvantages a)Reservoir: artificial lake created by a dam b) Main goal: capture & store runoff to be released as needed to control floods, generate electricity & supply water for farming and cities c) Also provide recreational activities d) There are 800,000 dams worldwide e) They have increased reliable runoff by 1/3 and hold 3-6 times as much water than flows in rivers & produce about 20% of electricity

  29. Fig. 13-13, p. 328

  30. 13-3 Is Building More Dams the Answer? f) They have displaced 40-80 million people, flooded productive land, & impaired some important ecological services g) About 1/5 of F W fish and plant species are extinct or endangered due to dams & water withdrawals destroying free flowing rivers h) Reservoirs loose large amounts of water and eventually fill in (about 50yrs) i) About 85% of US dams will be 50 by 2020

  31. 13-3 Is Building More Dams the Answer? 3) Rivers are running dry & lakes are shrinking a) Dams and withdrawal can reduce flow & prevent river water from reaching the sea b) Only 21 of the 177 longest rivers run freely from source to sea. c) Climate change will worsen the situation in many areas d) Many smaller rivers have totally disappeared e) some lakes and seas are shrinking and disappearing because of water diversion

  32. Fig. 13-17a, p. 332

  33. Case Study: The Colorado River Basin— An Overtapped Resource (pg 327) • 2,300 km through 7 U.S. states, 14 Dams and reservoirs, Located in a desert area within the rain shadow of the Rocky Mountains, Water supplied mostly from snowmelt of the Rocky Mountains • Supplies water and electricity for more than 25 million people, Irrigation of crops, Recreation • Four Major problems • Colorado River basin has very dry lands • Modest flow of water for its size • Legal pacts allocated more water for human use than it can supply • Water flowing to the mouth of the river has dropped

  34. Case Study: The Colorado River Basin— An Overtapped Resource

  35. Case Study: China’s Three Gorges Dam (page 328) • World’s largest hydroelectric dam and reservoir • Benefits • Electricity-producing potential is huge • Holds back the Yangtze River floodwaters • Allows cargo-carrying ships • Harmful effects • Displaces about 5.4 million people • Built over a seismic fault • Rotting plant and animal matter producing CH4 • Will the Yangtze River become a sewer?

  36. 13-4 Is Transferring Water from One Place to Another the Answer? 1) Ca transfers massive amounts of water a) California water project used dams, pumps & aqueducts to transport water from northern to southern Ca b) Northern and Southern Californians feud over how the state’s water should be allocated c) Agriculture consumes ¾ of the water withdrawn in Ca d) Northern argues that it degrades the Sacramento River, threatens fisheries and reduces the ability to flush pollutants out of the bay & it is wasted

  37. Fig. 13-16, p. 331

  38. 13-4 Is Transferring Water from One Place to Another the Answer? d) It is projected that global warming will reduce the water available in in Ca and many will have to leave the southern part Case study: The Aral Sea disaster page 330 • Large-scale water transfers in dry central Asia • Salinity • Wetland destruction and wildlife • Fish extinctions and fishing • Wind-blown salt • Water pollution • Climatic changes • Restoration efforts

  39. 2) China Plans a Massive Transfer of Water a) He Chinese government has started to transfer water from 3 southern rivers to its northern provinces b) Cost will be about 62.5 Billion and use a series of canals, dams, reservoirs and pumping stations c) By 2050 the system will transfer 10 times more water than the Ca project d) Critics worry that pollutants will contaminate northern water supplies, could damage southern ecosystems

  40. 2) China Plans a Massive Transfer of Water e) Others point to increased desertification in north eroding biodiversity & reducing water for 96 million people f) Northern has large populations, intensive agriculture and rapid industrialization g) Also it will reduce overpumping of aquifers h) However, climate models predict northern China will become more wet due to global warming

  41. 13-5 Is Converting Salty Seawater to Freshwater the Answer? 1) Desalination: removing of salt from sea water 2) Distillation: using evaporation-condensation 3) Reverse osmosis: uses high pressure to push water through a membrane 4) Problems a) high cost and energy footprint b) chemicals used kill many marine organisms c) produces briny water, that contaminates coastal areas or land when dumped 5) Currently desalination is practical for water-short, wealthy countries or cities

  42. Science Focus: The Search for Improved Desalination Technology (pg 333) • Desalination on offshore ships • Solar or wind energy • Better membranes • Better disposal options for the brine waste • Reduce water needs, conserve water

  43. 13-6 How Can We Use Water More Sustainably? 1) Reducing water waste a) Estimated that 65-70% of water is wasted through evaporation, leaks and other means b) It may be feasible to reduce this to 15% and meet most of the world’s water needs in the future c) Increasing efficiency would decrease burden on wastewater plants and reduce the need for new projects d) Main cause of waste is low cost of water, due to subsidies

  44. 13-6 How Can We Use Water More Sustainably? e) Users have little incentive to invest in water-saving technologies f) Prices will increase with scarcity g) Lack of subsidies for improving efficiency also leads to waste h) Goals of these subsidies would be to improve irrigation efficiency and to use inexpensive means to collect rainwater and pipe it where needed 2) Can we cut irrigation waste? a) About 60% of irrigation water is lost

  45. 13-6 How Can We Use Water More Sustainably? d) Flood irrigation: loses 40%, pumps water down ditches to crop e) Center pivot, low pressure sprinklers: uses pumps to spray water on a crop 80% of water reaches crop LEPA puts 90-95% f) Drip irrigation (microirrigation): most efficient, delivers small amounts of water to crops through perforated tubing, costly but 90-95% efficient, crop yields are 20-90% more (only 1% of crop fields) g) Capital cost of a new drip system is 1/10 as much per hectare as conventional systems.

  46. Fig. 13-18, p. 335

  47. Fig. 13-121 p. 335

  48. 13-6 How Can We Use Water More Sustainably? 3) Developing countries use low-tech methods a) Treadle pumps: human powered pumps to move water b) Rain water harvesting: c) Polyculture, agroforestry, perennials (control weeds) d) Fog-catcher nets: plastic nets funneling fog into containers

  49. Fig. 13-20, p. 337

  50. 13-6 How Can We Use Water More Sustainably? 4) We can cut water waste at home a) Chemical, paper, oil, coal metals & processed food uses almost 90% of water by US industries b) Many recycle the water to reduce costs c) Most could be redesigned to waste less water d) Flushing: largest use of domestic water in US newer toilet us no more than 1.6 gal (6.1 L) e) Low-flow shower heads can cut water in half (saves 5,000 gallons per person per year)

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