Chapter 11Chapter 11WaterWater

Section 1 – Water ResourcesSection 1 – Water Resources

The Water CycleThe Water Cycle

EvaporationEvaporation– Heat of the sun changes water on the Earth’s surface Heat of the sun changes water on the Earth’s surface

from liquid to gas.from liquid to gas. CondensationCondensation

– Water vapor cools enough to return to a liquid state.Water vapor cools enough to return to a liquid state. PrecipitationPrecipitation

– Liquid or solid water falls from the clouds to the Earth.Liquid or solid water falls from the clouds to the Earth. TranspirationTranspiration

– Plants release water vapor from their leaves into the Plants release water vapor from their leaves into the air.air.

Major Processes in Water CycleMajor Processes in Water Cycle

Global Water DistributionGlobal Water Distribution

3% Freshwater: 97% 3% Freshwater: 97% SaltwaterSaltwater

Surface WaterSurface Water

Fresh water on Earth’s land surfaceFresh water on Earth’s land surface Found in lakes, rivers, streams, and wetlandsFound in lakes, rivers, streams, and wetlands Provide drinking water, water for crops, food, Provide drinking water, water for crops, food,

power for industry, and means of transportationpower for industry, and means of transportation River Systems – as streams and rivers move River Systems – as streams and rivers move

across the land they form this flowing network of across the land they form this flowing network of waterwater

Watershed – a region drained by, or one Watershed – a region drained by, or one that contributes water to, a stream, lake, or that contributes water to, a stream, lake, or other body of water.other body of water.

Divide – Any ridge between two streams Divide – Any ridge between two streams along which precipitation runs off.along which precipitation runs off.– Continental Divide Continental Divide

GroundwaterGroundwater

Water beneath the Earth’s surface in sediment Water beneath the Earth’s surface in sediment and rock formations.and rock formations.

Water table – as water travels beneath the Water table – as water travels beneath the Earth’s surface, it eventually reaches a level Earth’s surface, it eventually reaches a level where rocks and soil are saturated with waterwhere rocks and soil are saturated with water– Wet regions – may be at Earth’s surfaceWet regions – may be at Earth’s surface– Deserts – hundreds of meters below Earth’s surfaceDeserts – hundreds of meters below Earth’s surface

Aquifers – an underground formation containing Aquifers – an underground formation containing groundwatergroundwater

Porosity – the percentage of the total volume of a Porosity – the percentage of the total volume of a rock that has spaces (holes)rock that has spaces (holes)

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

The Recharge Zone – an area of the Earth’s The Recharge Zone – an area of the Earth’s surface from which water percolates down into an surface from which water percolates down into an aquifer.aquifer.– Environmentally sensitive areas.Environmentally sensitive areas.– Aquifers can take tens of thousands of years to Aquifers can take tens of thousands of years to

recharge.recharge. Wells – a hole that is dug or drilled to reach Wells – a hole that is dug or drilled to reach

groundwatergroundwater

Section 2 – Water Use and Section 2 – Water Use and ManagementManagement

Global Water UseGlobal Water Use

Three major uses for water: residential use, Three major uses for water: residential use, agricultural use, and industrial useagricultural use, and industrial use– Most fresh water used to irrigate cropsMost fresh water used to irrigate crops

Residential Water UseResidential Water Use

The average person in the US uses about The average person in the US uses about 80 gallons of water every day.80 gallons of water every day.– In India – 41 Liters = ~11 gallonsIn India – 41 Liters = ~11 gallons

Water TreatmentWater Treatment– Potable – water that is safe to drinkPotable – water that is safe to drink– Pathogens – Organisms that cause illness or Pathogens – Organisms that cause illness or

disease that are removed during the water disease that are removed during the water treatment process.treatment process.

Industrial Water UseIndustrial Water Use

Industry accounts for 19% of water used in Industry accounts for 19% of water used in the world.the world.– Most used to cool power plants. Most used to cool power plants.

Agricultural Water UseAgricultural Water Use

Irrigation – a method of providing plants with Irrigation – a method of providing plants with water from sources other than direct water from sources other than direct precipitation.precipitation.

Water Management ProjectsWater Management Projects

Water Diversion Projects – To supply dry Water Diversion Projects – To supply dry regions with water, all or part of a river can be regions with water, all or part of a river can be diverted into canals that carry water across diverted into canals that carry water across great distances.great distances.– Colorado RiverColorado River

Dams and ReservoirsDams and Reservoirs– Dam – a structure built across a river to control the Dam – a structure built across a river to control the

river’s flowriver’s flow– Reservoir – when a river is dammed, and artificial Reservoir – when a river is dammed, and artificial

lake forms behind the dam.lake forms behind the dam.

Water ConservationWater Conservation

In Agriculture – Drip irrigation systems – In Agriculture – Drip irrigation systems – deliver small amounts of water directly to deliver small amounts of water directly to roots of plantsroots of plants

In Industry – recycling of cooling water and In Industry – recycling of cooling water and wastewater. Instead of discharging into a wastewater. Instead of discharging into a river, businesses recycle water.river, businesses recycle water.

At Home – Low-flow toilets and shower At Home – Low-flow toilets and shower headsheads

Solutions for the FutureSolutions for the Future

Desalination – the process of removing salt Desalination – the process of removing salt from salt water.from salt water.

Transporting Water – Greek Islands water Transporting Water – Greek Islands water usage has increased due to tourists. Water usage has increased due to tourists. Water is shipped in regularly from the mainland in is shipped in regularly from the mainland in plastic bags.plastic bags.

Section 3 – Water PollutionSection 3 – Water Pollution

Water PollutionWater Pollution

The introduction of chemical, physical, or The introduction of chemical, physical, or biological agents into water that degrade water biological agents into water that degrade water quality and adversely affect the organisms that quality and adversely affect the organisms that depend on the water.depend on the water.– Industrialization and rapid human population growthIndustrialization and rapid human population growth

Point-Source PollutionPoint-Source Pollution

Pollution discharged from a single pointPollution discharged from a single point– Can be identified and traced to the sourceCan be identified and traced to the source– Factory, wastewater treatment plant, leaking oil Factory, wastewater treatment plant, leaking oil

tankertanker

Non-Source PollutionNon-Source Pollution

Comes from different sources and are often Comes from different sources and are often difficult to identify.difficult to identify.– If a farm, a road, or any other land surface in a If a farm, a road, or any other land surface in a

watershed is polluted, runoff from a rainstorm watershed is polluted, runoff from a rainstorm can carry the pollution into a nearby river, can carry the pollution into a nearby river, stream or lake.stream or lake.

– Spraying lawn chemicals, use of storm drains to Spraying lawn chemicals, use of storm drains to dispose of used motor oildispose of used motor oil

Principal Water PollutantsPrincipal Water Pollutants

Wastewater – water that contains wastes from homes or Wastewater – water that contains wastes from homes or industry.industry.

Treating wastewater – Treating wastewater – – Filtration – wastewater passed through large screen to Filtration – wastewater passed through large screen to

remove solid objectsremove solid objects– First settling tank – wastewater sent into large tank, where First settling tank – wastewater sent into large tank, where

smaller particles sink to the bottom and form sewer sludgesmaller particles sink to the bottom and form sewer sludge– Aeration tank – mixed with oxygen and bacteria. Bacteria Aeration tank – mixed with oxygen and bacteria. Bacteria

use oxygen and feed on wastesuse oxygen and feed on wastes– Second settling tank – bacteria removed from sludgeSecond settling tank – bacteria removed from sludge– Chlorination or UV light– Chlorine added to disinfect water or Chlorination or UV light– Chlorine added to disinfect water or

UV used to disinfect water.UV used to disinfect water.

Sewage sludge – product of wastewater Sewage sludge – product of wastewater treatment.treatment.– Often incinerated, and then ash is buried in Often incinerated, and then ash is buried in

secure landfill.secure landfill.– If toxicity can be reduced to safe levels – sold If toxicity can be reduced to safe levels – sold

as fertilizer.as fertilizer.– Also combined with clay to make bricks.Also combined with clay to make bricks.

Principal Water Pollutants, cntd.Principal Water Pollutants, cntd. Thermal Pollution – when the temperature of a Thermal Pollution – when the temperature of a

body of water increases. Leads to decrease in body of water increases. Leads to decrease in oxygen.oxygen.– Power plants release warm water into a lake or riverPower plants release warm water into a lake or river– Massive fish killsMassive fish kills

Groundwater Pollution – any pollution of the Groundwater Pollution – any pollution of the surface water can affect groundwatersurface water can affect groundwater– Herbicides, chemical fertilizers, underground storage Herbicides, chemical fertilizers, underground storage

tankstanks

Ocean PollutionOcean Pollution

Oil spills – 1989 Exxon Valdez oil spill in Oil spills – 1989 Exxon Valdez oil spill in Prince William Sound, Alaska.Prince William Sound, Alaska.

125 Olympic-sized swimming pools of oil 125 Olympic-sized swimming pools of oil dumped into Oceandumped into Ocean

Ocean PollutionOcean PollutionDeep Horizon Oil SpillDeep Horizon Oil Spill–   Largest accidental marine oil spill in the history of Largest accidental marine oil spill in the history of

the petroleum industry.the petroleum industry. Flowed unabated for three months in 2010Flowed unabated for three months in 2010

– Skimmer ships, floating containment booms, Skimmer ships, floating containment booms, anchored barriers, sand-filled barricades along anchored barriers, sand-filled barricades along shorelines, and dispersants were used in an attempt shorelines, and dispersants were used in an attempt to protect hundreds of miles of beaches, wetlands, to protect hundreds of miles of beaches, wetlands, and estuaries from the spreading oil.and estuaries from the spreading oil.

– Even the amount of oil that was spilled remains a mystery. Federal officials estimated the amount at more than 200

million gallons of crude, while acknowledging the estimate could be off by plus or minus 20 million gallons.

BP, which leased the Deepwater Horizon rig, argued in December that the government’s oil spill size estimate was 20% to 50% too high.

Deepwater Horizon oil spill - May 24, 2010

Cleaning Up Water PollutionCleaning Up Water Pollution

Clean Water Act of 1972 – to restore and Clean Water Act of 1972 – to restore and maintain the chemical, physical, and maintain the chemical, physical, and biological integrity of the nation’s watersbiological integrity of the nation’s waters– Set a national goal of making all natural surface Set a national goal of making all natural surface

water fit for swimming and fishing by 1983.water fit for swimming and fishing by 1983.– Banned pollutant discharge into surface water Banned pollutant discharge into surface water

after 1985.after 1985.