WATER RESOURCES AND WATER POLLUTION

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CHAPTER 12

• WATER RESOURCES AND WATER POLLUTION

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Water wars in the Middle East

• These are not the only water waters!
• Phoenix and Tuscon, Arizona
• Georgia and Alabama
• Resolving the problems will require
• regional cooperation to allocate water supplies
• slowed population growth
• efficiency in using water
• increased water prices to encourage conservation
  and improve irrigation efficiency

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Waters Unique properties

• Strong forces of attraction (hydrogen bonds)
  between molecules of water --gt
• liquid water stores much heat and changes
  temperature very slowly
• lots of heat is required to evaporate water
• so.water exists as a liquid over wide range of
  temperature
• and it has high surface tension

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Waters Unique Properties -2

• Also because of unique molecular attractions
• water expands as it freezes, becomes less dense,
  and floats
• water can dissolve a variety of compounds
• it can dissolve and carry nutrients and wastes
  around in living systems
• it can remove and dilute water soluble wastes of
  civilization

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Supply, renewal and use of water resources

• 97 is salt water - cannot be used to drink,
  irrigate or for industry
• Most of the 3 of fresh water is frozen in ice
  caps.
• 0.592 is available fresh water - constantly
  recycled in hydrologic cycle
• Water availability is far from uniform - due to
  variations in precipitation areas needing the
  most often have the least.

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Fresh water sources

• Precipitation - surface water flows into streams,
  etc.
• A watershed is a drainage basin - collects water
  which ultimately will go to a specific place
• Precipitation - may infiltrate ground filling
  voids existing there - called ground water
• zone of saturation - upper boundary is water table

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Fresh Water Sources

• Aquifers are porous, water filled areas - can be
  confined or unconfined
• Recharge areas- where water enters aquifers
• Discharge points- water leaves aquifers
• Water mining (digging wells) withdraws water from
  aquifers - can be depleted
• Aquifers are nonrenewable -on human scale

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How do we use worlds fresh water

• We use 54 of global surface runoff
• Global withdrawal rate is growing exponentially -
  but varies worldwide
• 70 used for irrigation - up to 80 evaporates
• 20 used for industry - see amounts on p. 290
• 10 used by residences and cities
• Differences in water supply and varying uses in
  U.S. regions east versus. west

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Too Little Water

• Causes of water scarcity
• dry climate
• drought
• desiccation of soil
• water stress - low per capita water availability
• 40 population lives in water-short areas
• compare current with projections for 2025
• Wasteful and unsustainable use of normally
  available supplies is the problem

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Too little water - 2

• Conflicts over water supplies are growing
• Water tables are falling on every continent much
  river water never reaches the sea
• Access to water is a key foreign policy and will
  become increasingly important
• Where water is abundant, it is often not where it
  is needed.

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Increasing water supplies

• Ways to increase supplies
• Build dams and reservoirs to store runoff
• Bring in surface water from another area
• Withdraw groundwater
• Desalinate salt water - make fresh water
• Improve efficiency of water use
• Developed countries transport water to where
  needed
• Developing countries - settle where water is

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Dam Reservoirs -Pros Cons

• Water can be used for hydroelectric power,
  irrigation, control of flooding, carried to
  people by aqueducts and recreation
• Bad effects include death of river organisms,
  destruction of estuaries, salt water
  contamination of aquifers near coast
• What are pros and cons of proposed Three Gorges
  project to dam the Yangtze river?

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Watershed transfers - Pros Cons

• Transfer by tunnels, aquaducts under ground
  pipes from water rich to water poor
• always an effect - You cant do just one thing
• California water project carries water from north
  to southern California
• Opponents say too much transported water is
  wasted and negatively affects N. California
• Groundwater already being withdrawn too fast

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Watershed transfers - 2

• James Bay Watershed Transfer Project
• Proposed construction of 600 dams and dikes
  affecting 19 giant rivers - huge watershed
• Project will flood boreal forest and tundra and
  displace indigenous Indians
• Phase I completed Phases II and III postponed
  due to Indian opposition, contract cancellation,
  and no need for more electricity

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Watershed transfers -3

• Soviet Union - water transfer by worlds longest
  irrigation canal has shrunk Aral Sea
• seas salinity has tripled
• 54 less surface area 80 volume reduction
• supply rivers are trickles
• extinction of native fish, bird and other species
• destruction of forests cropland
• sea is no longer a thermal buffer
• water table contaminated

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Groundwater withdrawal - pros cons

• Advantages over surface water use
• can be removed year round
• not lost by evaporation
• development cheaper than surface water system
• Overuse of groundwater has led to
• aquifer depletion
• aquifer subsidence
• intrusion of salt water into aquifers

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Groundwater withdrawal - pros cons

• Withdrawal in U.S. is 4x replacement rate
• Ogallala Aquifer
• Arid S.W. U.S
• Most other countries have water crises
• Coastal rapid withdrawal --gt salt intrusion
• To prevent groundwater depletion cut population
  growth, wise planting, use strains using less
  water, efficient irrigation

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Usefulness of desalination

• Removal of dissolved salt from water by
• distillation - evaporation then condensation
• reverse osmosis - pumping through salt excluding
  membrane
• 11,100 plants are very expensive to operate
• What to do with salt removed - put it in ocean?
  Or on land?
• Solar powered distillation plants?

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Cloud seeding and icebergs

• Silver iodide particles form condensation nuclei
  difficult in very dry areas
• cloud rustling
• Tow icebergs to water deficient areas - pump
  melted ice to cities

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Reduce water waste

• 65 - 70 of water used is wasted
• waste could be reduced to 15
• Benefits of water conservation
• reduce burden on wastewater plants and septic
  systems
• decrease surface and ground water pollution
• reduce of dams and water transfer systems
• slow depletion of groundwater aquifers
• save and energy to treat distribute water

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Why do we waste so much water?

• Government subsidies produce artificially low
  water prices
• Taxes born by all pay for subsidies
• Little incentive to use less water
• Need regional approach to water management.

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Irrigation Losses

• Only 40 of water diverted for irrigation reaches
  crops
• Flood irrigation delivers too much water
• Irrigation canals can be lined /or covered
• Low-energy precision application sprinklers
• Trickle or drip irrigation systems minimize
  evaporation
• Computer systems monitor soil moisture

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Water waste in industry, homes and businesses

• 78 household water - toilets and bathing
• Xeriscaping uses dry-adapted plants
• Leaky pipes waste 50 of water
• Lack of water metering provide no incentive to
  save household water
• Water saving devices help
• Educate the public on ways to save water

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Water waste in industry, homes and businesses - 2

• S.W. droughts --gt water demand reduction with
  economic hardship
• Use of gray water need to separate water flows
  from homes from flows from industry
• Automated recycling systems
• Collect and use rainwater for nondrinking
• Coordinate water policies of national and local
  governments

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Too Much Water

• Causes of flooding
• water overflows natural channel to floodplain
• floodplains, including wetlands
• provide natural flood and erosion control
• help maintain how water quality
• contribute to groundwater recharging
• people living in floodplains face consequences

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Too Much Water - 2

• Flooding kills damages but benefits are
• provide productive farmland
• recharge groundwater under plains
• refill wetlands
• Human effect on flooding
• removal of water-absorbing vegetation
• living on flood plains
• urbanization - highways, parking lots, buildings

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Living dangerously in Bangladesh

• Most densely populated
• 80 of country is floodplain great floods occur
  every 4 years now due to
• population growth, deforestation, farming
• clearing protective coasting mangrove forests
• devastating cyclones
• Bangladesh, Bhutan, China, India, and Nepal need
  to cooperate in reforestation and flood control
  measures reduce population

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Reduction of flood risks

• Channelization - straighten and deepen stream -
  controversial due to erosion effects
• Artificial levees and embankments - often cause
  damage downstream --gt levee races
• Flood control dams can overflow or fill with
  sediment
• Measures provide false sense of security

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Reduction of flood risks - 2

• Floodplain management
• construct flood frequency curve - historical
  records and vegetation examination
• use data to develop plan
• prohibit buildings or activities in high risk
  zones
• elevate or flood proof allowed structures
• construct floodway
• Federal flood Disaster Protection Act -1973
• requires floodplain development regulations
• federal flood insurance

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Major Water Pollutants

• Disease-causing agents (pathogens)
• bacteria
• viruses
• protozoa
• parasitic worms
• water quality indicator - coliform bacteria
• Oxygen-demanding wastes - Biological Oxygen
  Demand - oxygen needed by aerobic decomposers

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Major Water Pollutants - 2

• Water-soluble inorganic chemicals - acids, salts,
  toxic metals
• make water unfit to drink, harm fish and other
  aquatic life, lower crop yields, accelerate
  corrosion of metals exposed to water
• Inorganic nutrients - nitrates phosphates
• cause excessive algae and water plant growth
  which then die, decompose and use up oxygen

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Major Water Pollutants - 3

• Organic chemicals - oil, gasoline, plastics,
  pesticides, cleaning solvents, detergents
• Sediment -insoluble particles suspended in water
• reduces photosynthesis disrupts food webs,
  carries harmful substance, destroys feeding
  spawning grounds, clogs and fills lakes
• Water-soluble radioactive isotopes
• Heated water - thermal pollution
• Introduction of non-native species

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Water Pollution Sources

• Point sources are at specific places and are
  relatively easy to identify, monitor and
  regulate
• factories
• sewage treatment plants
• active and abandoned underground mines
• offshore oil wells
• tankers

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Water Pollution Sources - 2

• Nonpoint sources cannot be traced to single
  source of discharge
• acid deposition
• runoff of chemicals into surface water
• seepage into the ground from croplands
• Nonpoint sources 57 - 64 of total mass of
  pollutants entering waters

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Stream Pollution Problems

• Streams can recover relatively quickly from
  degradable, oxygen-demanding wastes and excess
  heat - natural recovery depends on
• dilution and bacterial decay as long as there is
• no overloading of pollutants
• maintenance of flow
• Decomposition of biodegradable waste requires
  oxygen --gt oxygen-sag curve

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Stream pollution reduction progress

• What if cities removed drinking water down stream
  rather than up-stream?
• Good News Water pollution control laws have
  improved wastewater treatment plants and
  decreased discharges from industry
• Cuyahoga River (Ohio) burned today is good
• River cleanup is occurring in Canada, Japan and
  Europe

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Stream pollution reduction progress

• Bad news - disasterous fish kills and drinking
  water contamination continues
• industrial release of toxic inorganic and organic
  chemicals
• malfunctioning sewage treatment plants
• nonpoint runoff of pesticides and nutrients
• Developing nations and eastern Europe have little
  wastewater treatment sewage and industrial waste
  in waters

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Lake pollution problems

• Dilution less useful - little flushing
• Stratification of layers reduces oxygen
• More vulnerable to sediment atmospheric fallout
• Many pollutants are biologically magnified
• Eutrophication - natural nutrient enrichment of
  lakes is intensified near cities - cultural
  eutrophication

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Lake pollution problems - 2

• Cultural eutrophication prevention
• advanced waste treatment
• phosphate limits or bans
• soil conservation land use control
• Clean-up
• dredge bottom sediments remove weeds
• control undesirable plant growth
• pump in air

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Great Lakes pollution - good news

• Great Lakes pollution control program-1972
  brought about improvements by
• treatment of sewage and industrial waste
• banning phosphate detergents, cleaners, etc
• Resulted in
• decreased phosphate, coliforms, toxic chemical
• decreased algae blooms
• increased dissolved oxygen
• most swimming beaches reopened

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Great Lakes pollution - bad news

• lt 3 of shoreline is safe
• nonpoint land runoff exceeds industrial wastes
• grasshopper effect - pollution arrived from
  elsewhere and then carried elsewhere
• many fish should not be eaten
• low water levels - will get lower
• Should more bans be made?

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Genetic pollution in Great Lakes

• Zebra mussels from Europe --gt effects
• decrease food for other species
• clogging irrigation pipes
• shut down water intakes
• foul beaches grow on docks
• 700 million per year cost
• store and pass on pollutants (biomagnification)
• will spread to other waters
• round goby feed on mussels but also on other
  species

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Groundwater pollution problems

• Aquifers easy to deplete slow to replenish
• Contaminated groundwater slow to clean
• slow movement and decomposition
• Sources of groundwater contamination
• underground storage tanks
• landfills
• abandoned hazardous waste dumps
• liquid hazardous disposal in deep wells
• livestock waste storage lagoons near aquifers

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How to protect groundwater?

• Groundwater clean up is too expensive, so..
• We must prevent contamination by
• monitoring aquifers near landfills and tanks
• requiring leak detection systems
• require underground tank liability insurance
• ban or strictly regulate hazardous waste disposal
• in deep injection wells or in landfills
• require above ground storage with leak detectors

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Ocean Pollution

• Oceans can dilute, disperse and degrade large
  amounts of raw sewage, sewage sludge, oil and
  some industrial waste in deep-water areas
• But some marine life is less resilient to
  pollution
• Effect of pollutants on coastal areas
• 40 of population lives near coast
• wetlands, estuaries, coral reefs and mangrove
  swamps
• many diseases from pollution affect coastal
  residents
• eutrophication has led to vast dead zones

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Chesapeake Bay

• Largest U.S. estuary - a pollution sink
• receives drainage from 9 large rivers and 141
  smaller streams
• shallow and poorly flushed by ocean
• point and nonpoint sources and air pollutants
• Chesapeake Bay Program (1980s) has reduced
  pollutants but zebra mussels will soon invade

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Pollutants dumped into oceans

• U.S. coastline industrial waste dumping stopped
  (still occurs in other countries)
• Barges and ships continue to dump dredge spoils
• Sewage sludge banned in U.S. (continues in other
  countries)
• Agreements not to dump difficult to enforce
• London Dumping Convention, 1972

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Oil effects on ocean ecosystems

• Sources of release
• tanker accidents and offshore drilling blowouts
  important, but more from normal operations
• waste oil is dumped, spilled and leaked
• Effects depend on
• amount and type of oil (crude or refined)
• distance from shore of release
• time of year, weather, water temperature and
  currents

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Exxon Valdez Oil Spill

• 1989 - oil pumped from Alaskas North slope
  fields to port of Valdez to tankers
• Worst oil spill in U.S waters
• Lack of double hull on Exxon Valdez
• 8.5 billion accident Exxon spent 2.2 billion
• Disaster showed importance of pollution
  prevention need for energy efficiency and use of
  renewable energy

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Protection of Coastal Waters

• Prevention
• Separate sewage from storm runoff
• No ocean dumping of sludge and hazards
• Protect ecologically sensitive areas
• Use ecological land-use planning
• Require double hulled oil tankers
• Recycle used oil
• Reduce genetic pollution

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Protection of Coastal Waters - 2

• Cleanup
• Improve oil spill cleanup capabilities
• Require at least secondary treatment of sewage
• Or use wetlands or environmentally acceptable
  methods for cleanup

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Preventing and reducing water pollution

• Water pollution from nonpoint sources
• reduce fertilizer runoff into surface waters
• use agricultural methods using less fertilizer
• vegetation buffer zones
• use biological control of pests or IPM
• reduce nonfarm fertilizer use
• control runoff from feedlots etc
• reforest critical watersheds

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Preventing reducing water pollution point
sources - legal approach

• Water Pollution Control Act of 1972, etc. have
  increased number of fishable swimmable waters
• EPA developed discharge trading policy
• Continuing problems meat industry pollutant
  runoffs, industrial wastes, antiquated sewage
  systems
• Should Clean Water Act be strengthened or
  weakened?

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Preventing reducing water pollution point
sources - technological approach

• Regular cleaning of rural suburban septic tanks
• Urban sewage surface runoff separation
• Sewage treatment plant purification levels
• primary - mechanical removal of solids
• secondary - aerobic bacteria degradation
• trickling filters or activated sludge process
• advanced sewage treatment -chemical physical

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What to do with sewage sludge

• In U.S. 55 is dumped in landfills or
  incinerated 9 composted 36 applied to land
• Sewage sludge must be treated to kill harmful
  bacteria before use as fertilizer
• Better to prevent toxic and hazardous wastes from
  reaching sewage treatment plants

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Work with nature to treat sewage

• Arcata, California uses artificial wetland
• sedimentation --gtaeration in oxidation ponds--gt
  release into artificial marshes where bacteria
  plants cleanup water marsh is bird sanctuary
• Phoenix, Arizona - creating wetlands for part of
  its sewage
• Use of greenhouse lagoons with sunlight and
  natural food chains to clean sewage

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Safe drinking water?

• 1/4 of people in developing countries do not have
  safe drinking water
• May lead to increase in cancer and liver deaths
• Tremendous cost of providing low-cost safe water
  and sanitation
• Treatment of water for drinking in cities -
  similar to waste water treatment

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Protection of quality of drinking water

• U.S. Safe Drinking Water Act of 1974- set
  standards - maximum contaminant levels
• attempts have been made to weaken standards by
  water polluting industries environmentalists
  want to strengthen standards
• privately owned wells not required to meet
  standards
• lack of notification of contaminated drinking
  water

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Protection of quality of drinking water -2

• Bottled water is not always safer (International
  Bottled Water Association)
• Check out safety of tap water before buying
  bottled water or
• Installation of home water purifiers - look for
  EPA approval

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Sustainable use of water resources

• Underlying forces leading to unsustainable use
• depletion or degradation of a shared resource
• population growth
• unequal distribution or access

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Sustainable use of water resources

• Sustainable use - use must not exceed recharge
  requires integrated plan for water use, sewage
  treatment, and water pollution of a common basin
• We must switch to prevention by
• reduce toxicity and volume
• reuse wastewater
• recycle pollutants