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ENVIRONMENTAL SCIENCE. CHAPTER 11: Water Resources and Water Pollution. Three Big Ideas from This Chapter: #1 One of the world’s major environmental problems is growing shortages of freshwater in parts of the world. Three Big Ideas from This Chapter: #2 We can use H 2 O more sustainably by:

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environmental science

ENVIRONMENTALSCIENCE

CHAPTER 11:Water Resources and Water Pollution

slide2

Three Big Ideas from This Chapter:

#1 One of the world’s major environmental problems is growing shortages of freshwater in parts of the world.

slide3

Three Big Ideas from This Chapter:

  • #2 We can use H2O more sustainably by:
  • cutting water waste
  • raising water prices
  • slowing population growth
  • protecting aquifers, forests, & other ecosystems that store & release water.
slide4

Three Big Ideas from This Chapter:

  • #3 Reducing water pollution requires:
  • preventing pollution
  • working with nature in treating sewage
  • cutting resource use & waste
  • reducing poverty
  • slowing population growth.
slide5

Colorado River Story

  • 1400 miles thru ___ states
  • ___ dams & reservoirs
  • Electricity for _____________ people
  • Water for ____% of U.S. crops & livestock
slide8

Colorado River Story

  • Water for desert cities
  • Very little reaches the
will we have enough usable water
Will We Have Enough Usable Water?
  • We’re using freshwater unsustainably by:
  • Now: One of every ____ people insufficient access to clean water
importance availability of water
Importance & Availability of Water
  • Earth as a watery world ____%
  • Poorly managed resource
  • Water access  global health issue
    • 3900 children < 5 yrs die each ____ from waterborne disease
  • Water is
importance availability of water1
Importance & Availability of Water
  • National and global security issue
  • Environmental issue
  • Freshwater availability –
surface water
Surface Water
  • Surface runoff
  • Watershed (drainage) basin
  • Reliable runoff – _____ of total
  • Runoff use
    • Domestic – ___%
    • Agriculture – ___%
    • Industrial – ___%
freshwater resources in united states
Freshwater Resources in United States
  • Uneven distribution
  • Contamination by agriculture & industry
  • Groundwater withdrawal: ~_____% of total use
slide19

Average annual precipitation (centimeters)

81-122

More than 122

Less than 41

41-81

Acute shortage

Shortage

Adequate supply

Metropolitan regions with population greater than 1 million

Stepped Art

Fig. 11-4, p. 241

freshwater resources in united states1
Freshwater Resources in United States
  • Arid & semiaridWest:
    • ____% of water to irrigate thirsty crops
    • Water hot spots
    • Southwest: “permanent drying” by _____
  • Water tables are _________________
  • ____ states to face water shortages by 2013
slide21

Washington

North

Dakota

Montana

Oregon

Idaho

South

Dakota

Wyoming

Nebraska

Nevada

Utah

Kansas

Colorado

California

Oklahoma

Arizona

New

Mexico

Texas

Highly likely conflict potential

Substantial conflict potential

Moderate conflict potential

Unmet rural water needs

Fig. 11-5, p. 242

freshwater shortages
Freshwater Shortages
  • Causes of water scarcity
    • ______________________
    • ______________________
    • ______________________
    • ______________________
  • 2050: ____ countries will face water stress!
  • 1 of 7 people – no regular access to clean water
  • Potential international conflicts over water
slide23

Natural capital degradation:

stress on the world’s major river basins

Asia

Europe

North

America

Africa

South

America

Australia

Stress

None

High

Fig. 11-6, p. 243

how can we increase water supplies
How Can We Increase Water Supplies?
  • Groundwater (supply cities & grow food)
  • pumped from aquifers
slide25

Using dams, reservoirs, & transport systems

  • to provide water to arid regions:
  • - has increased H2O supplies in some areas
  • - but has disrupted ecosystems
  • - displaced _____________________ people.
how can we increase water supplies1
How Can We Increase Water Supplies?

Convert ocean water to freshwater

Freezing:

slide27

Electrodialysis:

porous membranes filter out (-) & (-) salt ions using an applied electric current.

slide28

Reverse Osmosis pressure from salt in water, forces water thru a water permeable membrane.

slide29

Convert ocean water to freshwater, but:

  • High cost
  • Resulting salty brine must be disposed of without harming ecosystems.
increasing freshwater supplies
Increasing Freshwater Supplies
  • Withdrawing groundwater
  • Dams and reservoirs
  • Transporting surface water
  • Desalination
  • Water conservation
slide32

Trade-Offs

Withdrawing Groundwater

Advantages

Disadvantages

Useful for drinking and

irrigation

Aquifer depletion from

overpumping

Sinking of land (subsidence)

from overpumping

Available year-round

Aquifers polluted for

decades or centuries

Exists almost everywhere

Saltwater intrusion into

drinking water supplies near

coastal areas

Renewable if not

overpumped or

contaminated

Reduced water flows into

surface waters

No evaporation losses

Increased cost and

contamination from deeper

wells

Cheaper to extract than

most surface waters

Fig. 11-7, p. 244

groundwater withdrawal
Groundwater Withdrawal
  • Most aquifers are renewable
groundwater withdrawal1
Groundwater Withdrawal
  • U.S. groundwater withdrawn _____ times faster then it’s replenished
  • _____________ aquifer
groundwater withdrawal2
Groundwater Withdrawal
  • California’s Central Valley and agriculture
slide36

Groundwater

Overdrafts:

High

Moderate

Minor or none

Fig. 11-8, p. 244

slide37

Solutions

Groundwater Depletion

Prevention

Control

Raise price of water to

discourage waste

Waste less water

Tax water pumped from

wells near surface waters

Subsidize water conservation

Limit number of wells

Set and enforce minimum

stream flow levels

Divert surface water in wet

years to recharge aquifers

Do not grow water-intensive

crops in dry areas

Fig. 11-9, p. 245

slide38

Are Deep Aquifers the Answer?

  • Could have enough water to supply billions of
  • people for centuries
  • Concerns:
    • _______________________
    • Geological and ecological impacts of pumping them __________________
    • No treaties to govern water rights
    • Costs unknown
slide39

Provides

irrigation water

above and

below dam

Flooded land

destroys forests

or cropland and

displaces people

Large losses of

water through

evaporation

Provides water

for drinking

Deprives

downstream

cropland and

estuaries of

nutrient-rich silt

Reservoir useful

for recreation

and fishing

Risk of failure

and devastating

downstream

flooding

Can produce

cheap electricity

(hydropower)

Reduces

downstream

flooding

Disrpupts

migration and

spawning of

some fish

Fig. 11-10, p. 246

overtapped colorado river basin
Overtapped Colorado River Basin
  • Only small amount reaches Gulf of California
    • Threatened species
  • Climate change will likely ___________flows
  • Less water in Southwest
    • ______________________________
  • ______ behind dams not reaching delta
  • and will eventually _____________________
slide42

35

30

Hoover Dam

completed (1935)

25

20

Flow (billion cubic meters)

15

Glen Canyon

Dam completed

(1963)

10

5

0

1910

1920

1930

1940

1950

1960

1970

1980

1990

2000

Year

Fig. 11-11, p. 247

california water project
California Water Project
  • Dams, pumps, aqueducts
  • Southern California would otherwise be desert
  • Climate change will reduce water availability in California
  • People in southern California may have to move
  • Groundwater already being depleted
slide44

CALIFORNIA

NEVADA

Shasta Lake

UTAH

Sacramento

River

Oroville Dam and

Reservoir

Feather

River

Lake Tahoe

North Bay

Aqueduct

Sacramento

San Francisco

Hoover Dam

and Reservoir

(Lake Mead)

South Bay

Aqueduct

Fresno

San Joaquin Valley

San Luis Dam

and Reservoir

Colorado

River

Los Angeles

Aqueduct

California Aqueduct

ARIZONA

Colorado River

Aqueduct

Santa Barbara

Central Arizona

Project

Los Angeles

Phoenix

Salton Sea

San Diego

Tucson

MEXICO

Fig. 11-12, p. 247

slide46

Aral Sea Disaster:

  • Large-scale water transfers in dry central Asia
  • Water loss and salinity increase
  • Wetland destruction and wildlife
  • Fish extinctions hurt fishing industry
slide47

1976

2006

  • Aral Sea Disaster:
  • Wind-blown salt
  • Water pollution
  • Climatic changes
  • Restoration efforts
slide48

How Can We Use Water More Sustainably?

  • cutting _________________________
  • raising ________________________
  • slowing population growth
  • protecting
slide49

Reducing Water Waste

  • Benefits of water conservation
    • Worldwide – __________% loss
    • Evaporation, leaks
    • Can be reduced to ____%
  • Increase cost of water use
    • End subsidies for wasteful water use
    • Provide subsidies for efficient water use
slide50

Reducing Water Waste

  • Improve irrigation efficiency:
    • Center pivot
    • Low-pressure sprinkler
    • Precision sprinklers
    • Drip irrigation
  • Use less in homes and businesses
slide51

Center pivot

(efficiency 80% with low-pressure sprinkler and 90–95% with LEPA sprinkler)

Drip irrigation

(efficiency 90–95%)

Water usually pumped from underground and sprayed from mobile boom with sprinklers.

Gravity flow

(efficiency 60% and 80% with surge valves)

Above- or below-ground pipes or tubes deliver water to individual plant roots.

Water usually comes from an aqueduct system or a nearby river.

Stepped Art

Fig. 11-14, p. 251

environmental science1

ENVIRONMENTALSCIENCE

CHAPTER 11:Water Resources and Water Pollution

PART 2

slide57

How To Reduce Threat of Flooding?

  • Protecting more wetlands
  • Protecting natural vegetation in watersheds
  • Not building in areas that frequently flood.
slide58

Benefits of Floodplains

  • Highly productive wetlands
  • Provide natural flood and erosion control
  • Maintain high water quality
  • Recharge groundwater
  • Fertile soils
  • Nearby rivers for use and recreation
  • Flatlands for urbanization and farming
slide61

Floods:

  • Deposit ________________ on floodplains
  • Deadly & destructive
  • Human activities worsen floods
  • Failing dams and water diversion
  • Hurricane Katrina and Gulf Coast
  • Climate change: ____________________
slide63

Tree plantation

Diverse ecological habitat

Evapotranspiration decreases

Evapotranspiration

Roads destabilize hillsides

Trees reduce soil erosion from heavy rain and wind

Overgrazing accelerates soil erosion by water and wind

Winds remove fragile topsoil

Agricultural land

Agricultural land is flooded and silted up

Gullies and landslides

Tree roots stabilize soil

Heavy rain erodes topsoil

Vegetation releases water slowly and reduces flooding

Silt from erosion fills rivers and reservoirs

Rapid runoff causes flooding

Stepped Art

Fig. 11-19, p. 254

case study floodplains of bangladesh
Case Study: Floodplains of Bangladesh
  • Dense population on coastal floodplain
  • Moderate floods maintain ______________
  • Increased frequency of large floods
  • Development in the Himalayan foothills
  • Destruction of ________________________
slide66

Solutions

Reducing Flood Damage

Prevention

Control

Preserve forests on

watersheds

Straighten and deepen

streams (channelization)

Preserve and restore

wetlands in floodplains

Build levees or floodwalls

along streams

Tax development on

floodplains

Use floodplains primarily

for recharging aquifers,

sustainable agriculture and

forestry

Build dams

Fig. 11-20, p. 256

slide67

How Can We Deal with Water Pollution?

  • Streams can cleanse themselves
    • if not overloaded them
    • or flows reduced
slide68

How Can We Deal with Water Pollution?

  • Reducing water pollution
    • requires preventing it
    • Use nature in treating sewage
    • cutting resource use and waste,
    • reducing poverty
    • slow pop growth.
water pollution sources
Water Pollution Sources
  • Point sources
    • Discharge at specific locations
    • Easier to identify, monitor, regulate
water pollution sources1
Water Pollution Sources

Nonpoint sources

Broad, diffuse areas

Runoff of chemicals and sediment

Agriculture

stream pollution
Stream Pollution
  • Natural recovery processes
  • Oxygen sag curve
    • D.O.= ________________________
    • B.O.D.= ________________________
  • Effective regulations in U.S.
  • Problems in developing countries
slide73

Point source

Normal clean water organisms(Trout, perch, bass,mayfly, stonefly)

Pollutant-

tolerant fishes (carp, gar)

Fish absent, fungi, sludge

worms,

bacteria (anaerobic)

Pollutant-

tolerant fishes (carp, gar)

Normal clean water organisms

(Trout, perch, bass,

mayfly, stonefly)

8 ppm

Types of organisms

8 ppm

Dissolved oxygen (ppm)

Clean Zone

Biological

oxygen demand

Recovery Zone

Septic Zone

Decomposition Zone

Clean Zone

Fig. 11-21, p. 258

individuals matter john beal
Individuals Matter: John Beal
  • Restored Hamm Creek in WA State
  • ___________________________
  • “All sustainability is local”
lake pollution
Lake Pollution
  • Dilution less effective than with streams
    • _____________________________
    • _____________________________
  • Lakes are more vulnerable than streams
cultural eutrophication
Cultural Eutrophication
  • Nitrate- & phosphate-containing effluents
  • Dense colonies of plants, algae, cyanobacteria
  • Can lead to die-off of fish & other animals
  • Prevention limit phosphate & nitrate use
  • Lakes can be cleaned, and can recover
slide79

1970’s Lake Erie eutrophication.

Canada & US  Great Lakes

Water Quality Agreement.

groundwater pollution
Groundwater Pollution
  • Pollution sources
  • Slow flow, dilution, dispersion
  • Low dissolved oxygen
  • Fewer bacteria
  • Cooler temperatures
groundwater pollution1
Groundwater Pollution
  • Long time scale for natural cleansing
    • Degradable wastes –
    • Slowly degradable wastes –
    • Non-degradable wastes –
slide82

Polluted air

Hazardous waste

injection well

Pesticides

and fertilizers

Deicing

road salt

Coal strip

mine runoff

Buried gasoline

and solvent tanks

Cesspool,

septic tank

Gasoline station

Pumping

well

Water

pumping well

Waste lagoon

Sewer

Landfill

Leakage

from faulty

casing

Accidental

spills

Discharge

Confined

aquifer

Unconfined freshwater aquifer

Groundwater

flow

Confined freshwater aquifer

Fig. 11-23, p. 260

extent of groundwater pollution
Extent of Groundwater Pollution
  • Global scale – not much known
  • Monitoring is very expensive
  • Underground fuel tank leakage
  • Arsenic
  • Protecting groundwater  prevention is best
  • & least expensive
slide85

Solutions

Groundwater Pollution

Prevention

Cleanup

Pump to surface, clean,

and return to aquifer

(very expensive)

Find substitutes for toxic

chemicals

Keep toxic chemicals out of

the environment

Install monitoring wells near

landfills and underground

tanks

Inject microorganisms to

clean up contamination

(less expensive but still

costly)

Require leak detectors on

underground tanks

Ban hazardous waste disposal

in landfills and injection wells

Store harmful liquids in

aboveground tanks with leak

detection and collection

systems

Pump nanoparticles of

inorganic compounds to

remove pollutants (still

being developed)

Fig. 11-24, p. 261

purifying drinking water
Purifying Drinking Water
  • Developed countries:
    • Reservoir storage
    • Purification plant
  • Developing countries - no purification plants:
    • Clear plastic bottle in sun, w/ black side
    • LifeStraw
science focus is bottled water the answer
Science Focus: Is Bottled Water the Answer?
  • 500-1000 times the cost of tap water
    • Americans spent $15 billion in 2007
  • About _____ is ordinary tap water
  • About ____% of bottled water contaminated
  • Water testing standards lower than for tap H2O
  • Environment: energy use, pollution
ocean pollution
Ocean Pollution
  • Coastal areas – highly productive ecosystems
    • Occupied by ___% of population
    • Coastal populations will double by __________
    • About ___% marine pollution originates on land
  • Ocean dumping controversies
slide90

Industry

Nitrogen oxides

from autos and

smokestacks,

toxic chemicals,

and heavy metals in

effluents flow into

bays and estuaries.

Cities

Toxic metals and

oil from streets and

parking lots pollute

waters; sewage

adds nitrogen and

phosphorus.

Urban sprawl

Bacteria and viruses from

sewers and septic tanks

contaminate shellfish beds

and close beaches; runoff of

fertilizer from lawns adds

nitrogen and phosphorus.

Construction sites

Sediments are washed into

waterways, choking fish and plants,

clouding waters, and blocking sunlight.

Farms

Runoff of pesticides, manure, and

fertilizers adds toxins and excess

nitrogen and phosphorus.

Red tides

Excess nitrogen causes

explosive growth of toxic

microscopic algae,

poisoning fish and

marine mammals.

Closed

shellfish beds

Closed

beach

Oxygen-depleted

zone

Toxic sediments

Chemicals and toxic metals

contaminate shellfish beds,

kill spawning fish, and

accumulate in the tissues

of bottom feeders.

Oxygen-depleted zone

Sedimentation and algae

overgrowth reduce sunlight,

kill beneficial sea grasses, use

up oxygen, and degrade habitat.

Healthy zone

Clear, oxygen-rich

waters promote growth

of plankton and sea

grasses,and support fish.

Fig. 11-26, p. 263

science focus oxygen depletion in the northern gulf of mexico
Science Focus: Oxygen Depletion in the Northern Gulf of Mexico
  • Mouth of Mississippi River in spring and summer
  • Suffocates __________________________
  • _____________________ eutrophication
  • Caused by ________________________ in Mississippi watershed
  • Need less and more intelligent use of fertilizers
  • Need better flood control
slide93

Missouri River

Mississippi

River Basin

Ohio River

Mississippi River

Depleted oxygen

Stepped Art

Fig. 11-A, p. 265

case study ocean pollution from oil
Case Study: Ocean Pollution from Oil
  • Crude and refined petroleum
  • Tanker accidents – Exxon Valdez
  • Urban and industrial runoff is largest source
effects of oil pollution on ocean ecosystems
Effects of Oil Pollution on Ocean Ecosystems
  • Volatile organic hydrocarbons
    • Kill larvae
    • Destroy natural insulation and buoyancy of birds and mammals
effects of oil pollution on ocean ecosystems1
Effects of Oil Pollution on Ocean Ecosystems

Heavy oil

Sinks and kills bottom organisms

Coral reefs die

oil cleanup methods
Oil Cleanup Methods
  • Current methods recover no more than 15%
  • Prevention is most effective method
    • Control runoff
    • Double-hull tankers
slide102

Solutions

Coastal Water Pollution

Prevention

Cleanup

Reduce input of toxic

pollutants

Improve oil-spill cleanup

capabilities

Separate sewage and

storm lines

Use nanoparticles on

sewage and oil spills to

dissolve the oil or sewage

(still under development)

Ban dumping of wastes

and sewage by ships in

coastal waters

Ban ocean dumping of

sludge and hazardous

dredged material

Require secondary treatment of coastal sewage

Regulate coastal

development, oil drilling,

and oil shipping

Use wetlands, solar-aquatic,

or other methods to treat

sewage

Require double hulls for

oil tankers

Fig. 11-27, p. 264

preventing non point source pollution
Preventing Non-point Source Pollution
  • Mostly agricultural waste
  • Use _________________ to reduce soil erosion
  • Reduce fertilizer use
preventing non point source pollution1
Preventing Non-point Source Pollution
  • Use plant buffer zones around fields and animal feedlots
  • Keep feedlots away from slopes, surface water, and flood zones
  • Integrated pest management
  • Organic farming methods
laws for reducing point source pollution
Laws for Reducing Point Source Pollution
  • Clean Water Act
  • Water Quality Act
  • Discharge trading controversies
    • Cap-and-trade of pollutants
case study reducing water pollution from point sources in the u s
Case Study: Reducing Water Pollution from Point Sources in the U.S.
  • Impressive achievements since 1972 law
  • Bad news – 2006 survey
    • ____%of lakes and ____%of streams too polluted for fishing and swimming
    • Runoff polluting ____ of 10 rivers
    • Fish caught in _____of waterways unsafe to eat
  • Gasoline storage tanks:
sewage treatment systems
Sewage Treatment Systems
  • Rural and suburban areas – septic tanks
  • Urban areas – wastewater treatment plants
    • Primary sewage treatment – physical process
    • Secondary sewage treatment – biological process
    • Chlorination – bleaching and disinfection
slide108

Primary

Secondary

Chlorine

disinfection tank

Bar screen

Grit chamber

Settling tank

Aeration tank

Settling tank

To river, lake,

or ocean

Sludge

Raw sewage

from sewers

(kills bacteria)

Activated sludge

Air pump

Disposed of in

landfill or ocean or applied to cropland,

pasture, or rangeland

Sludge digester

Sludge drying bed

Fig. 11-28, p. 268

improving sewage treatment
Improving Sewage Treatment
  • Systems that exclude hazardous & toxic chemicals
  • Require businesses to remove harmful chemicals before sewage sent to treatment plant
  • Reduce or eliminate use of toxic chemicals
  • Composting toilet systems
  • Wetland-based sewage treatment
science focus treating sewage by working with nature
Science Focus: Treating Sewage by Working with Nature
  • Living machines
  • Tanks with increasingly complex organisms
  • Artificially created wetlands
  • Scientific principles of sustainability