Chapter 11Chapter 11WaterWater

World Water DistributionWorld Water Distribution

Total:Total:

97% salt water97% salt water

3% freshwater3% freshwater

Freshwater:Freshwater:

70% glaciers70% glaciers

29% aquifers29% aquifers

1% lakes, rivers, 1% lakes, rivers, streamsstreams

Water is unequally distributed across Earth’s Water is unequally distributed across Earth’s surfacesurface

Different regions possess vastly different amounts of Different regions possess vastly different amounts of groundwater, surface water, and precipitationgroundwater, surface water, and precipitation

Many areas with high population density are water- Many areas with high population density are water- poor and face serious water shortagespoor and face serious water shortages

Surface WaterSurface Water Lakes, rivers, streams, Lakes, rivers, streams,

wetlands, estuarieswetlands, estuaries Watershed: the area Watershed: the area

of land that is drained of land that is drained by a riverby a river

River system: the River system: the flowing network of flowing network of water draining a river water draining a river basinbasin

Watersheds of the world (see Watersheds of the world (see pgs. 270-271)pgs. 270-271)

GroundwaterGroundwater

GroundwaterGroundwater: water : water that is beneath the that is beneath the earth’s surfaceearth’s surface

Water tableWater table: the : the upper level of water upper level of water undergroundunderground

AquiferAquifer: underground : underground formation that formation that contains groundwatercontains groundwater

AquifersAquifers

Most are made of materials like rock, Most are made of materials like rock, sand, gravel with spaces in which the sand, gravel with spaces in which the water can be held like a sponge (see water can be held like a sponge (see pgs. 274-275)pgs. 274-275)

Water can be tapped from aquifers for Water can be tapped from aquifers for use by people; if used too much and use by people; if used too much and too quickly, it can go dry (Ogallala too quickly, it can go dry (Ogallala Aquifer case study, pgs. 272-273)Aquifer case study, pgs. 272-273)

AquifersAquifers Aquifers can be refilled as Aquifers can be refilled as

water percolates down water percolates down through thethrough the recharge zone, recharge zone, may take a long timemay take a long time

Porosity – Porosity – amount of space amount of space between particles of the between particles of the rockrock

Permeability – Permeability – ability of the ability of the rock or soil to allow water rock or soil to allow water to flow through itto flow through it

Pollution can enter the Pollution can enter the groundwater through the groundwater through the recharge zone (think about recharge zone (think about Silent SpringSilent Spring) – it can then ) – it can then travel to other places travel to other places through the underground through the underground water system, even water system, even showing up years latershowing up years later

The Ogallala AquiferThe Ogallala Aquifer

The world’s largest The world’s largest known aquiferknown aquifer

Underlies the Great Underlies the Great Plains of the U.S.Plains of the U.S.

Its water has allowed Its water has allowed farmers to create farmers to create the most bountiful the most bountiful grain-producing grain-producing region in the worldregion in the world

Water UseWater Use

Which category has the highest

use overall in the world?

Water UseWater Use

1. Industrial 1. Industrial – manufacturing, producing power – manufacturing, producing power (including reservoirs by dams), cooling of power (including reservoirs by dams), cooling of power plantsplants

Global Water Use: IndustryGlobal Water Use: Industry

How does water use compare in developing and How does water use compare in developing and developed countries?developed countries?

Which countries have more than 50% of their water Which countries have more than 50% of their water used by industries?used by industries?

Water UseWater Use

2. Agricultural 2. Agricultural – irrigation of crops– irrigation of crops

Global Water Use: Global Water Use: AgricultureAgriculture

Which countries have the highest Which countries have the highest percent of their water use dedicated percent of their water use dedicated to agriculture?to agriculture?

Water UseWater Use3. Residential3. Residential (=municipal) – (=municipal) –

drinking, cooking, cleaningdrinking, cooking, cleaning

Residential Water UseResidential Water Use

Guess the gallons it takes Guess the gallons it takes to…to…

Take a shower:Take a shower:50 gallons50 gallons

Flush the toilet:Flush the toilet:6 gallons6 gallons

Large load of laundry:Large load of laundry:60 gallons60 gallons

Brushing teeth, water running:Brushing teeth, water running:2 gallons2 gallons

Dishwasher load:Dishwasher load:10 gallons10 gallons

Washing face/hands:Washing face/hands:5 gallons5 gallons

Water Use CaculatorWater Use Caculator

http://www.tampagov.net/dept_Water/http://www.tampagov.net/dept_Water/information_resources/information_resources/Saving_water/Saving_water/Water_use_calculator.aspWater_use_calculator.asp

Drinking Water TreatmentDrinking Water TreatmentSteps (pgs. 276-277):Steps (pgs. 276-277):1. First filtration – removes large trash, 1. First filtration – removes large trash,

objects, large organisms like fish and objects, large organisms like fish and musselsmussels

Drinking Water TreatmentDrinking Water Treatment2. Coagulation or flocculation – 2. Coagulation or flocculation – chemicals are chemicals are

added to the water; bacteria and other small added to the water; bacteria and other small impurities stick together to form flocs and settle impurities stick together to form flocs and settle out of the waterout of the water

Drinking Water TreatmentDrinking Water Treatment3. Second filtration – layers of sand, gravel, 3. Second filtration – layers of sand, gravel,

coal used to filter remaining impuritiescoal used to filter remaining impurities

Drinking Water TreatmentDrinking Water Treatment4. Chlorination – chlorine added to stop 4. Chlorination – chlorine added to stop

bacterial growthbacterial growth

Drinking Water TreatmentDrinking Water Treatment5. Aeration – removes unwanted gases, 5. Aeration – removes unwanted gases,

improves odor and tasteimproves odor and taste

Drinking Water TreatmentDrinking Water Treatment6. Additional Treatments 6. Additional Treatments - depends on the - depends on the

community: may include addition of community: may include addition of fluoride which is good for teeth, addition fluoride which is good for teeth, addition of chemicals to soften hard watersof chemicals to soften hard waters

Drinking Water TreatmentDrinking Water Treatment

7. Potable (=drinkable) water is 7. Potable (=drinkable) water is pumped to homes for residential pumped to homes for residential use.use.

Water Treatment Plant Water Treatment Plant Virtual TourVirtual Tour

http://www.teachersdomain.org/resources/http://www.teachersdomain.org/resources/ess05/sci/ess/watcyc/h2otreatment/ess05/sci/ess/watcyc/h2otreatment/index.htmlindex.html

Water managementWater management

Water diversion projects bring water to Water diversion projects bring water to areas that need itareas that need it

Central Arizona Project Aqueduct – brings water from the Colorado River to dry areas of Arizona, multiple uses (drinking water, recreation, power, etc.)

We divert – and deplete – surface We divert – and deplete – surface waterwater

People have long diverted water to farm fields, homes, and cities

The once mighty Colorado River has been extensively dammed and diverted

The Colorado River is heavily divertedThe Colorado River is heavily diverted What water is left after all the diversions What water is left after all the diversions

comprises just a trickle into the Gulf of comprises just a trickle into the Gulf of CaliforniaCalifornia

On some days, water does not reach the gulfOn some days, water does not reach the gulf Diversion has drastically altered the river’s Diversion has drastically altered the river’s

ecologyecology

The Aral SeaThe Aral Sea Once the fourth-largest lake on Once the fourth-largest lake on

EarthEarth It has lost more than 80% of It has lost more than 80% of

its volume in just 45 years its volume in just 45 years The two rivers leading into the The two rivers leading into the

Aral Sea were diverted to Aral Sea were diverted to irrigate cotton fieldsirrigate cotton fields

Consequences of a shrinking seaConsequences of a shrinking sea 60,000 fishing jobs are gone60,000 fishing jobs are gone Pesticide-laden dust from the Pesticide-laden dust from the

lake bed is blown into the airlake bed is blown into the air The cotton cannot bring back The cotton cannot bring back

the region’s economythe region’s economy

Can the Aral Sea be saved?Can the Aral Sea be saved?

People may have People may have begun saving begun saving the northern part the northern part of the Aral Seaof the Aral Sea

Water managementWater management

Dams – purposes: Dams – purposes: flood control flood control hydroelectric power hydroelectric power creation of reservoirs for drinking water, creation of reservoirs for drinking water,

irrigation and recreationirrigation and recreation

Only a few major rivers remain undammedOnly a few major rivers remain undammed In remote regions of Canada, Alaska, In remote regions of Canada, Alaska,

and Russiaand Russia

A typical damA typical dam

Water managementWater managementCase Study: Glen Canyon Dam, AZCase Study: Glen Canyon Dam, AZ

List pros and consList pros and conshttp://video.nationalgeographic.com/video/player/environment/going-green-http://video.nationalgeographic.com/video/player/environment/going-green-

environment/conservation-in-action/glen-canyon.htmlenvironment/conservation-in-action/glen-canyon.html

Water managementWater management

Case Study: Three Gorges Dam, ChinaCase Study: Three Gorges Dam, Chinahttp://www.youtube.com/watch?v=NwFGyzllCJg&eurl=http://http://www.youtube.com/watch?v=NwFGyzllCJg&eurl=http://

www.theworldisnotflat.com/three-gorges-damwww.theworldisnotflat.com/three-gorges-dam

List pros and consList pros and cons

Benefits and drawbacks of Benefits and drawbacks of damsdams

Benefits:Benefits: Power generationPower generation Emission reductionEmission reduction Crop irrigationCrop irrigation Drinking waterDrinking water Flood controlFlood control ShippingShipping New recreational New recreational

opportunitiesopportunities

Drawbacks:Drawbacks: Habitat alterationHabitat alteration Fisheries declinesFisheries declines Population Population

displacementdisplacement Sediment captureSediment capture Disruption of floodingDisruption of flooding Risk of failureRisk of failure Lost recreational Lost recreational

opportunitiesopportunities

Are we running out of Are we running out of water?water?

Do you think water is a Do you think water is a renewable renewable resource?resource?

It is a renewable resource because it can It is a renewable resource because it can be replenished by nature (water cycle)be replenished by nature (water cycle)

However, if it is made unusable by However, if it is made unusable by pollution or removed from the ground pollution or removed from the ground faster than nature can replenish it, then faster than nature can replenish it, then it is considered nonrenewableit is considered nonrenewable

Will we see a future of water Will we see a future of water wars?wars?

Freshwater depletion leads to shortages, Freshwater depletion leads to shortages, which can lead to conflictwhich can lead to conflict 261 major rivers cross national borders261 major rivers cross national borders Water is a key element in hostilities among Water is a key element in hostilities among

Israel, Palestinians, and neighboring countriesIsrael, Palestinians, and neighboring countries Many nations have cooperated with Many nations have cooperated with

neighbors to resolve disputesneighbors to resolve disputes

Consequences of overuse of water Consequences of overuse of water resources:resources:

Groundwater is easily depleted Groundwater is easily depleted Aquifers recharge slowlyAquifers recharge slowly 1/3 of world population relies on groundwater1/3 of world population relies on groundwater

As aquifers become depletedAs aquifers become depleted Water tables dropWater tables drop Salt water intrudes in coastal areasSalt water intrudes in coastal areas Sinkholes = areas where ground gives way Sinkholes = areas where ground gives way

unexpectedlyunexpectedly Some cities (Venice, Mexico City) are slowly Some cities (Venice, Mexico City) are slowly

sinkingsinking Wetlands dry upWetlands dry up

Solutions can address Solutions can address supply or demandsupply or demand

Increasing supplyIncreasing supply Water can be transported through pipes Water can be transported through pipes

and aqueductsand aqueducts It can be forcibly appropriated from It can be forcibly appropriated from

weak communitiesweak communities

Can we “make” more usable water?Can we “make” more usable water?

DesalinationDesalinationDesalination is the process of removing salt Desalination is the process of removing salt

from salt water – may be answer to from salt water – may be answer to providing more water to a growing human providing more water to a growing human populationpopulation

It is expensive, requires fossil fuels, and It is expensive, requires fossil fuels, and produces concentrated salty waterproduces concentrated salty water

Solutions can address supply Solutions can address supply or demandor demand

Best solution is to lower demand, that is Best solution is to lower demand, that is to CONSERVE WATERto CONSERVE WATER Politically difficult in the short term Politically difficult in the short term Offers better economic returnsOffers better economic returns Causes less ecological and social damageCauses less ecological and social damage

Water conservationWater conservation

Agriculture – drip Agriculture – drip irrigation systemirrigation system

Water conservationWater conservation

Industry – recycle waterIndustry – recycle water

Residential demand can be Residential demand can be reduced outsidereduced outside

Water lawns at night, Water lawns at night, when evaporation is when evaporation is minimalminimal

XeriscapingXeriscaping = = landscaping using landscaping using plants adapted to arid plants adapted to arid conditionsconditions

Don’t wash driveways Don’t wash driveways and sidewalks with and sidewalks with waterwater

Water conservation in the Water conservation in the homehome

Residential – how can you conserve Residential – how can you conserve water?water?

Awareness of water use and conscious decisions to Awareness of water use and conscious decisions to reduce water use (shorter showers, turn off water reduce water use (shorter showers, turn off water when brushing teeth, etc.)when brushing teeth, etc.)

Low flow faucets, shower heads and toiletsLow flow faucets, shower heads and toilets Don’t use toilet as a waste basketDon’t use toilet as a waste basket Run dishwasher and washing machine only when Run dishwasher and washing machine only when

fullfull Fix leaky plumbingFix leaky plumbing