Water supply, use, and management lecture ppt_ch21

WaterWater
Supply,Supply,
UseUse
andand
ManagementManagement
Tanya j.Tanya j.

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

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

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

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.

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

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

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.

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.

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

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

 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.

 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.

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

 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.

 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.

 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

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

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

Sustainability and WaterSustainability and Water
 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.

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.

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.

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.

A Master Plan for WaterA Master Plan for Water
 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.

A Master Plan for WaterA Master Plan for Water
 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

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

Channelization and theChannelization and the
 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

Channelization and theChannelization and the
 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.

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

 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

 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.

 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.

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.

 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.

 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.

Water supply, use, and management lecture ppt_ch21

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Water supply, use, and management lecture ppt_ch21

Similar to Water supply, use, and management lecture ppt_ch21 (20)

Water supply, use, and management lecture ppt_ch21