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Water supply, use, and management lecture ppt_ch21

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  • 1. WaterWater Supply,Supply, UseUse andand ManagementManagement Tanya j.Tanya j.
  • 2. A Brief Global PerspectiveA Brief Global Perspective  We are facing a growing global water shortage linked toWe are facing a growing global water shortage linked to the food supply.the food supply.  Global hydrologic cycleGlobal hydrologic cycle  Transfers water from the atmosphere, to land, to oceans andTransfers water from the atmosphere, to land, to oceans and back to atmosphereback to atmosphere  97% in oceans97% in oceans  2% in ice2% in ice  Only 0.001% in atmosphereOnly 0.001% in atmosphere
  • 3. A Brief Global PerspectiveA Brief Global Perspective  At Earth’s surface water can be found in liquid, solid orAt Earth’s surface water can be found in liquid, solid or gaseous form.gaseous form.  Residence time varies from a few days to thousands ofResidence time varies from a few days to thousands of yearsyears  Amount of water for which all people, animals andAmount of water for which all people, animals and plants compete is less than 1%plants compete is less than 1%  Industrial production increases water useIndustrial production increases water use  Mass of water used 1000x total production of mineralsMass of water used 1000x total production of minerals
  • 4. Water Supply: A US ExampleWater Supply: A US Example  Amount of water vapor passing over the US every day ~Amount of water vapor passing over the US every day ~ 152,000 million m152,000 million m33  10% falls as precipitation (66% of which is evaporated or10% falls as precipitation (66% of which is evaporated or transpired)transpired)  Only 34% enters surface or groundwaterOnly 34% enters surface or groundwater
  • 5. DroughtsDroughts  Because there are large annual and regional variations inBecause there are large annual and regional variations in stream flow, even areas with high precipitation and runoffstream flow, even areas with high precipitation and runoff may suffer from droughts.may suffer from droughts.
  • 6. Some changes every body can seeSome changes every body can see  Salt content of the water has increasedSalt content of the water has increased  Dust storms from dry salt flatsDust storms from dry salt flats  Climate changesClimate changes  Winters colder, summers warmerWinters colder, summers warmer  Loss of fishing and decline of tourismLoss of fishing and decline of tourism
  • 7. Transport of WaterTransport of Water  Ancient civilizations constructed canals and aqueductsAncient civilizations constructed canals and aqueducts to transport waterto transport water  From distant river to where it is neededFrom distant river to where it is needed  In modern civilization water moved from areas ofIn modern civilization water moved from areas of abundant rain and snow fall to areas of high usageabundant rain and snow fall to areas of high usage  E.g. California moves water from north to southE.g. California moves water from north to south  E.g. NewYork City has had to obtain water from fartherE.g. NewYork City has had to obtain water from farther and farther awayand farther away
  • 8. SomeTrends in Water UseSomeTrends in Water Use  Trends in freshwater withdrawals by water-use categoriesTrends in freshwater withdrawals by water-use categories suggests that:suggests that:  1.The major uses of water are for irrigation and the1.The major uses of water are for irrigation and the thermoelectric industry.thermoelectric industry.  2. Water use for irrigation increased from 1950-1980. It2. Water use for irrigation increased from 1950-1980. It decreased and leveled off from 1985-2000decreased and leveled off from 1985-2000  due to better irrigation efficiency, crop type and higher energydue to better irrigation efficiency, crop type and higher energy costs.costs.
  • 9. SomeTrends in Water UseSomeTrends in Water Use  3. Water use by thermoelectric industry decreased slightly in3. Water use by thermoelectric industry decreased slightly in 1980, and stabilized in 1985.1980, and stabilized in 1985.  Due to reticulating water for coolingDue to reticulating water for cooling  4. Water for public and rural supplies continued to increase4. Water for public and rural supplies continued to increase through the period from 1950 to 2000through the period from 1950 to 2000  presumably related to the increase in human population.presumably related to the increase in human population.
  • 10. Water ConservationWater Conservation  The careful use and protection of water resourcesThe careful use and protection of water resources  Involves the quantity of water used and the qualityInvolves the quantity of water used and the quality  Important component of sustainable water useImportant component of sustainable water use  Expected that a number innovations will reduce the totalExpected that a number innovations will reduce the total withdrawalswithdrawals
  • 11. Agricultural UseAgricultural Use  Improved irrigation could reduce agricultural withdrawalsImproved irrigation could reduce agricultural withdrawals by 20 to 30%by 20 to 30%  Tremendous savings because ag is the biggest userTremendous savings because ag is the biggest user
  • 12. Agricultural UseAgricultural Use  Suggestions for conservation:Suggestions for conservation:  Price agricultural water to encourage conservationPrice agricultural water to encourage conservation  Use lined or covered canals that reduce seepage andUse lined or covered canals that reduce seepage and evaporation.evaporation.  Use computer monitoring and schedule release of waterUse computer monitoring and schedule release of water for maximum efficiency.for maximum efficiency.  Integrate the use of surface water and groundwater toIntegrate the use of surface water and groundwater to more effectively use the total resource.more effectively use the total resource.
  • 13. Agricultural UseAgricultural Use  Irrigate at times when evaporation is minimal, such as atIrrigate at times when evaporation is minimal, such as at night or in the early morning.night or in the early morning.  Use improved irrigation systems, such as sprinklers or dripUse improved irrigation systems, such as sprinklers or drip irrigation, that more effectively apply water to crops.irrigation, that more effectively apply water to crops.  Improve the soil to increase infiltration and minimize runoff.Improve the soil to increase infiltration and minimize runoff.  Encourage the development of crops that require less waterEncourage the development of crops that require less water or are more salt tolerant.or are more salt tolerant.
  • 14. Domestic UseDomestic Use  Accounts for about 10% of total national waterAccounts for about 10% of total national water withdrawalswithdrawals  But concentrated in urban areasBut concentrated in urban areas  May pose major local problemsMay pose major local problems
  • 15. Domestic UseDomestic Use  Water use can be substantially reduced by:Water use can be substantially reduced by:  In semi-arid regions, replace lawns with decorativeIn semi-arid regions, replace lawns with decorative gravels and native plants.gravels and native plants.  Use more efficient bathroom fixtures.Use more efficient bathroom fixtures.  Turn off water when not absolutely needed.Turn off water when not absolutely needed.  Flush the toilet only when really necessary.Flush the toilet only when really necessary.  Fix all leaks quickly.Fix all leaks quickly.
  • 16. Domestic UseDomestic Use  Purchase dishwashers and washing machines that minimizePurchase dishwashers and washing machines that minimize water consumption.water consumption.  Take a long bath rather than a long shower.Take a long bath rather than a long shower.  Sweep sidewalks and driveways.Sweep sidewalks and driveways.  Using gray water to water vegetation.Using gray water to water vegetation.  Water lawns and plants at cool times to reduce evaporation.Water lawns and plants at cool times to reduce evaporation.
  • 17. Domestic UseDomestic Use  Use drip irrigation and place water-holding mulch aroundUse drip irrigation and place water-holding mulch around garden plants.garden plants.  Plant drought-resistant vegetation.Plant drought-resistant vegetation.  Learn how to read the water meter to monitor forLearn how to read the water meter to monitor for unobserved leaks and record your conservation successes.unobserved leaks and record your conservation successes.  Use reclaimed waterUse reclaimed water
  • 18. Industry and Manufacturing UseIndustry and Manufacturing Use  Water conservation measures that can be taken byWater conservation measures that can be taken by industry:industry:  Using cooling towers that use little or no waterUsing cooling towers that use little or no water  In-plant water treatment and recyclingIn-plant water treatment and recycling
  • 19. Perception and Water UsePerception and Water Use  Perception of water is based partly on its price andPerception of water is based partly on its price and availability.availability.  If water is abundant and inexpensive, we don’t thinkIf water is abundant and inexpensive, we don’t think much about it.much about it.  If water is scarce or expensive, it is another matter.If water is scarce or expensive, it is another matter.  E.g. people inTucson pay about 100% more for waterE.g. people inTucson pay about 100% more for water than people in Phoenix.than people in Phoenix.  Tucson residence use less water per person per dayTucson residence use less water per person per day
  • 20. Sustainability and WaterSustainability and Water ManagementManagement  From a water supply use and management perspective,From a water supply use and management perspective, sustainable water use defined as:sustainable water use defined as:  use of water resources by people in a way that allows societyuse of water resources by people in a way that allows society to develop and flourish into an indefinite futureto develop and flourish into an indefinite future  W/o degrading the various components of the hydrologicW/o degrading the various components of the hydrologic cycle or the ecological systems that depend on it.cycle or the ecological systems that depend on it.
  • 21. Sustainable Water UseSustainable Water Use  General criteria:General criteria:  Develop water resources in sufficient volume to maintainDevelop water resources in sufficient volume to maintain human health and well-being.human health and well-being.  Provide sufficient water resources to guarantee the healthProvide sufficient water resources to guarantee the health and maintenance of ecosystems.and maintenance of ecosystems.  Ensure minimum standards of water quality for the variousEnsure minimum standards of water quality for the various users of water resources.users of water resources.
  • 22. Sustainable Water UseSustainable Water Use  Ensure that actions of humans do not damage or reduceEnsure that actions of humans do not damage or reduce long-term renewability of water resources.long-term renewability of water resources.  Promote the use of water-efficient technology and practice.Promote the use of water-efficient technology and practice.  Gradually eliminate water pricing policies that subsidize theGradually eliminate water pricing policies that subsidize the inefficient use of water.inefficient use of water.
  • 23. Water ManagementWater Management  Options for minimizing potential problems:Options for minimizing potential problems:  Alternating water supplies and managing existing suppliesAlternating water supplies and managing existing supplies betterbetter  Towing icebergsTowing icebergs  As price goes up many innovative programs are possible.As price goes up many innovative programs are possible.
  • 24. A Master Plan for WaterA Master Plan for Water ManagementManagement  New management philosophy is that surface water andNew management philosophy is that surface water and groundwater are both subject to natural flux with time.groundwater are both subject to natural flux with time.  In wet years, there is plenty of surface water, and the near-In wet years, there is plenty of surface water, and the near- surface groundwater resources are replenished.surface groundwater resources are replenished.  During dry years, specific plans to supply water on anDuring dry years, specific plans to supply water on an emergency basis must be in place and ready to use.emergency basis must be in place and ready to use.
  • 25. A Master Plan for WaterA Master Plan for Water ManagementManagement  Advanced planning may includeAdvanced planning may include  Drilling to wells that are presently isolatedDrilling to wells that are presently isolated  Reuse of waste waterReuse of waste water  Develop surface water and use groundwater in dry yearsDevelop surface water and use groundwater in dry years  In wet years pump excess surface water underground toIn wet years pump excess surface water underground to recharge groundwaterrecharge groundwater
  • 26. Water Management and theWater Management and the EnvironmentEnvironment  Often a good deal of controversy surrounds waterOften a good deal of controversy surrounds water developmentdevelopment  Dams, canals, wetlands modificationDams, canals, wetlands modification  Resolution of development involves input from a variety ofResolution of development involves input from a variety of government and public groupsgovernment and public groups
  • 27. Channelization and theChannelization and the EnvironmentEnvironment  Channelization of streams consists of straightening,Channelization of streams consists of straightening, deepening, widening, clearing, or lining existing streamdeepening, widening, clearing, or lining existing stream channels.channels.  Engineering technique that has been used to control floods,Engineering technique that has been used to control floods, improve drainage, control erosion, and improve navigationimprove drainage, control erosion, and improve navigation
  • 28. Channelization and theChannelization and the EnvironmentEnvironment  Adverse environmental effects, including theAdverse environmental effects, including the following:following:  Degradation of the stream’s hydrologic qualities;Degradation of the stream’s hydrologic qualities;  nearly all riffle flow, resulting in loss of important fish habitats.nearly all riffle flow, resulting in loss of important fish habitats.  Removal of vegetation along the watercourse, whichRemoval of vegetation along the watercourse, which removes wildlife habitats and shading of the water.removes wildlife habitats and shading of the water.  Downstream flooding where the channelized flow ends.Downstream flooding where the channelized flow ends.  Damage or loss of wetlands.Damage or loss of wetlands.  Aesthetic degradation.Aesthetic degradation.
  • 29. The Colorado RiverThe Colorado River  For its size has a modest flow but is one of the mostFor its size has a modest flow but is one of the most regulated and controversial bodies of water in the world.regulated and controversial bodies of water in the world.  Total flow was apportioned among various users in 1922Total flow was apportioned among various users in 1922  No water allowed for environmental purposesNo water allowed for environmental purposes  Water rarely flows into the Gulf, all stored and usedWater rarely flows into the Gulf, all stored and used upstream.upstream.  Damaged deltaDamaged delta
  • 30. The Colorado RiverThe Colorado River  Two largest reservoirs- Hoover Dam and Glen Canyon DamTwo largest reservoirs- Hoover Dam and Glen Canyon Dam  Stored about 80% of total in the basinStored about 80% of total in the basin  Represents a buffer of several years water supply.Represents a buffer of several years water supply.  Changing hydrology of the river changed other aspectsChanging hydrology of the river changed other aspects  Rapids, sediment load, and vegetationRapids, sediment load, and vegetation
  • 31. The Colorado RiverThe Colorado River  Record snowmelt in the Rocky Mountains in 1983 forcedRecord snowmelt in the Rocky Mountains in 1983 forced the release of water from Glen Canyon Damthe release of water from Glen Canyon Dam  Three times normal but similar to spring floods before theThree times normal but similar to spring floods before the dam was built.dam was built.  Beneficial to the river, highlighted the importance of floodsBeneficial to the river, highlighted the importance of floods in maintaining a natural state.in maintaining a natural state.
  • 32. The Colorado RiverThe Colorado River  As an experiment “flood” waters released in 1996As an experiment “flood” waters released in 1996  Two weeks at full floodTwo weeks at full flood  As a result 55 new sandbars formed and 75% of existingAs a result 55 new sandbars formed and 75% of existing sandbars increased in size, rejuvenated marshes andsandbars increased in size, rejuvenated marshes and backwaters.backwaters.  Hailed a success; hoped that what was learned can helpHailed a success; hoped that what was learned can help restore other river impacted by dams.restore other river impacted by dams.
  • 33. Global Water Shortage Linked toGlobal Water Shortage Linked to Food SupplyFood Supply Both surface water and groundwater are beingBoth surface water and groundwater are being stressed and depleted:stressed and depleted:  Groundwater in the United States, China, India,Groundwater in the United States, China, India, Pakistan, Mexico, and many other countries is beingPakistan, Mexico, and many other countries is being minedmined  used faster than it is being renewedused faster than it is being renewed  Large bodies of water—for example, the Aral Sea—areLarge bodies of water—for example, the Aral Sea—are drying up.drying up.  Large rivers, including the Colorado in the US and theLarge rivers, including the Colorado in the US and the Yellow in China, do not deliver any water to the ocean inYellow in China, do not deliver any water to the ocean in some seasons or years.some seasons or years.
  • 34. Global Water Shortage Linked toGlobal Water Shortage Linked to Food SupplyFood Supply  As human population grows there is growing concern thatAs human population grows there is growing concern that there won’t be sufficient water to grow the food to feed 8-there won’t be sufficient water to grow the food to feed 8- 9 billion people.9 billion people.  Food shortage linked to water resources a real possibility.Food shortage linked to water resources a real possibility.  Water also linked to energy (fuel to pump) as energy costWater also linked to energy (fuel to pump) as energy cost goes up so does cost of food.goes up so does cost of food.
  • 35. Global Water Shortage Linked toGlobal Water Shortage Linked to Food SupplyFood Supply  SolutionSolution  Control human population growthControl human population growth  Conserve and sustain water resourcesConserve and sustain water resources  Need to be proactive now before significant food shortagesNeed to be proactive now before significant food shortages develop.develop.

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