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Water Use and ManagementWater Use and Management

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Water as a ResourceWater as a Resource

Covers 71% of earth’s surfaceCovers 71% of earth’s surface Important propertiesImportant properties

– PolarPolar– Moves easilyMoves easily– Changes temperature slowlyChanges temperature slowly

Moderates earth’s climateModerates earth’s climate Protects living things from temperature fluctuationsProtects living things from temperature fluctuations

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Available WaterAvailable Water Total = 326 million cubic miles Total = 326 million cubic miles 97% in oceans97% in oceans 2.997% is locked up in ice caps 2.997% is locked up in ice caps

and glaciersand glaciers 0.003% is easily accessible 0.003% is easily accessible

– Soil moistureSoil moisture– GroundwaterGroundwater– Water vaporWater vapor– LakesLakes– StreamsStreams

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Surface WaterSurface Water Runoff flows into streams, lakes, wetlands Runoff flows into streams, lakes, wetlands

and reservoirsand reservoirs A A watershedwatershed or drainage basin or drainage basin

www.canaanvi.org/assistance/ watershed.asp

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GroundwaterGroundwater Precipitation infiltrates and Precipitation infiltrates and percolates percolates

– Pores, fractures, crevices, etc.Pores, fractures, crevices, etc.

Zone of aerationZone of aeration - Upper soil layers that hold both - Upper soil layers that hold both air and water.air and water.

Zone of saturationZone of saturation is at a depth were ground is is at a depth were ground is filled with water filled with water

Top of this zone is Top of this zone is water tablewater table– Falls and rises with weatherFalls and rises with weather

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Water CompartmentsWater Compartments

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GroundwaterGroundwater

AquifersAquifers - Porous layers of sand, gravel, or rock - Porous layers of sand, gravel, or rock lying below the water table.lying below the water table.– ArtesianArtesian - Pressurized aquifer intersects the surface. - Pressurized aquifer intersects the surface.

(Water flows without pumping)(Water flows without pumping) Recharge ZonesRecharge Zones

– Recharge rate is often very slow.Recharge rate is often very slow. groundwater is being faster then it can be replenishedgroundwater is being faster then it can be replenished

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GroundwaterGroundwater

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Objectives and Warmup: 12/1/10Objectives and Warmup: 12/1/10

Objectives:Objectives:– Explain why water is not equally distributed Explain why water is not equally distributed

throughout the world.throughout the world.

Warmup:Warmup:– What makes water not equally distributed throughout What makes water not equally distributed throughout

the world?the world?

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Use of Fresh WaterUse of Fresh WaterUnited States• Agriculture• Power plant cooling• Industry• Public

China• Agriculture• Industry• Public

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Water UseWater Use Globally Globally

70% soaked up by agriculture (mostly in the form of irrigation)

Industry accounts for 23% Domestic use (household,

drinking water, sanitation) accounts for about 7%

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Irrigation

Industry

Domestic

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Water UseWater Use

According to the UN, the average person needs a According to the UN, the average person needs a minimum of:minimum of:– 1.3 gallons of water per day to survive in a moderate 1.3 gallons of water per day to survive in a moderate

climate at an average activity levelclimate at an average activity level

– 13 gallons for drinking and cooking, bathing and 13 gallons for drinking and cooking, bathing and sanitationsanitation

The average person in the United States uses The average person in the United States uses between 80-100 gallons per day for drinking, between 80-100 gallons per day for drinking, cooking, bathing, and watering their yard. cooking, bathing, and watering their yard.

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FRESHWATER SHORTAGESFRESHWATER SHORTAGES

Estimated 1.5 billion people lack access to an Estimated 1.5 billion people lack access to an adequate supply of drinking water.adequate supply of drinking water.– Nearly 3 billion lack acceptable sanitation.Nearly 3 billion lack acceptable sanitation.– Globally, water supplies are abundant, but, along Globally, water supplies are abundant, but, along

with capital resources, are with capital resources, are unevenly distributed.unevenly distributed.

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Freshwater Shortage CausesFreshwater Shortage Causes

Dry climateDry climate Drought- a period in which precipitation is lower Drought- a period in which precipitation is lower

& evaporation is higher than normal& evaporation is higher than normal Desiccation- drying of the soil as a result of Desiccation- drying of the soil as a result of

deforestation & overgrazingdeforestation & overgrazing Water stress- more people relying on same Water stress- more people relying on same

amount of wateramount of water

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Global Precipitation PatternsGlobal Precipitation Patterns

Wright and Nebel, 2002.

Michael D. Lee Ph.D. Geography and Environmental Studies

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Rainfall DistributionRainfall Distribution

Rain falls unevenly over the planetRain falls unevenly over the planet Three factors control rainfallThree factors control rainfall

– Global atmospheric circulation-creates regions of Global atmospheric circulation-creates regions of high air pressure and low rainfallhigh air pressure and low rainfall

– Prevailing Winds-bring moisture to land from ocean; Prevailing Winds-bring moisture to land from ocean; areas far from oceans are usually dryareas far from oceans are usually dry

– Topography-mountains act as cloud formers and rain Topography-mountains act as cloud formers and rain catcherscatchers

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Rain Shadow EffectRain Shadow Effect

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Objectives and Warmup: 12/2/10Objectives and Warmup: 12/2/10

Objectives:Objectives:– Analyze how national and local water use are Analyze how national and local water use are

distributed and used throughout the US.distributed and used throughout the US.

Warmup:Warmup:– Calculate the per capita water use of Montana:Calculate the per capita water use of Montana:

Population 902 in thousandsPopulation 902 in thousands Water use 8290 in millionsWater use 8290 in millions

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Increasing the Supply of FreshwaterIncreasing the Supply of Freshwater

Dams and reservoirsDams and reservoirs Tapping groundwater suppliesTapping groundwater supplies DesalinizationDesalinization Towing icebergsTowing icebergs Water conservationWater conservation

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Dams and ReservoirsDams and Reservoirs

Advantages:Advantages:– Produce electricityProduce electricity– Irrigate land below the damIrrigate land below the dam– Divert water to cities, towns and rural areasDivert water to cities, towns and rural areas– RecreationRecreation

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Dams and Reservoirs ConsDams and Reservoirs Cons Environmental CostsEnvironmental Costs

– Upsets natural balance of water systemsUpsets natural balance of water systems– Croplands downstream are deprived of nutrient rich Croplands downstream are deprived of nutrient rich

silt silt – EvaporationEvaporation

Ecosystem LossesEcosystem Losses– Loss of wildlife habitatLoss of wildlife habitat– Migration and spawning of fish disruptedMigration and spawning of fish disrupted– Flooded land destroys forests or croplandFlooded land destroys forests or cropland

Displacement of PeopleDisplacement of People

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Colorado River BasinColorado River Basin

Diversion of water Diversion of water from Colorado River from Colorado River– Disputes between AZ, Disputes between AZ,

CA, Mexico CA, Mexico– Dams trap silt--- Dams trap silt---

more fertilizer needed more fertilizer needed– High levels of NaCl- High levels of NaCl-

salinizationsalinization

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Three Gorges Dams in China is forcing Three Gorges Dams in China is forcing relocation of 1.2 million peoplerelocation of 1.2 million people

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Tapping Groundwater SuppliesTapping Groundwater Supplies About ½ of the drinking water in the US is About ½ of the drinking water in the US is

pumped from aquiferspumped from aquifers AdvantagesAdvantages

– Year-round useYear-round use– Renewable if not overpumped or contaminatedRenewable if not overpumped or contaminated– No evaporation lossesNo evaporation losses– Often less expensiveOften less expensive

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Tapping Groundwater SuppliesTapping Groundwater Supplies DisadvantagesDisadvantages

– Water table loweringWater table lowering– OverpumpingOverpumping– Sinking of land (subsidence) when water removedSinking of land (subsidence) when water removed– Chemical contaminationChemical contamination– Saltwater intrusion into drinking water supplies near Saltwater intrusion into drinking water supplies near

coastal areascoastal areas

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Cone of Depression and Saltwater Cone of Depression and Saltwater IntrusionIntrusion

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Ogallala AquiferOgallala Aquifer

Underlies 8 states from Underlies 8 states from SD to TX SD to TX

Held more water than all Held more water than all freshwater on Earthfreshwater on Earth

Water shortagesWater shortages

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DesalinizationDesalinization Removing salt from sea water: reverse osmosisRemoving salt from sea water: reverse osmosis

– currently 3-4x more expensivecurrently 3-4x more expensive

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Towing IcebergsTowing Icebergs

Carry fresh water to places that need itCarry fresh water to places that need it– How can it be done? Would it be economically How can it be done? Would it be economically

sound?sound?

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Water Efficiency and ConservationWater Efficiency and Conservation Change in personal habitsChange in personal habits Fix leaky pipesFix leaky pipes Water–saving toilets, faucets, & shower headsWater–saving toilets, faucets, & shower heads Plant drought–tolerant vegetation in residential Plant drought–tolerant vegetation in residential

communities located in arid & semi–arid areascommunities located in arid & semi–arid areas Increase efficiency of irrigationIncrease efficiency of irrigation

– drip irrigation, computer monitoring, center-pivotdrip irrigation, computer monitoring, center-pivot

Use recycled waterUse recycled water– treat gray water from showers, washing machines for reusetreat gray water from showers, washing machines for reuse

EducationEducation

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