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Water and Water Pollution

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Water pollution. Climatic changes. Restoration efforts. Shrinking Aral Sea. Fig. 11-11, p. 245 ... Water Pollution: Types, Effects, and Sources. What is water ... – PowerPoint PPT presentation

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Title: Water and Water Pollution


1
Water and Water Pollution
  • Chapter 11

2
Water Conflicts in the Middle East
  • Water shortages
  • Nile River
  • Jordan Basin
  • Tigris and Euphrates rivers
  • Peacefully solving the problems

Fig. 11-1, p. 236
3
Water Conflicts in the Middle East
Fig. 11-1, p. 236
4
Importance and Availability of Water
  • Why is water so important?
  • Earth as a watery world
  • Water as a wasted resource
  • Tiny fraction of Earth water is fresh
  • Hydrologic cycle
  • Water pollution
  • Water haves and have-nots

5
Earths Water Budget
All water
Fresh water
Readily accessible fresh water
Groundwater 0.592
Biota 0.0001
Rivers 0.0001
Lakes 0.007
0.014
Fresh water 2.6
Atmospheric water vapor 0.001
Oceans and saline lakes 97.4
Ice caps and glaciers 1.984
Soil moisture 0.005
Fig. 11-2, p. 238
6
Groundwater
  • Zone of saturation
  • Water table
  • Aquifers
  • Natural recharge

7
Groundwater Systems
Unconfined Aquifer Recharge Area
Evaporation and transpiration
Evaporation
Precipitation
Confined Recharge Area
Runoff
Flowing artesian well
Recharge Unconfined Aquifer
Stream
Well requiring a pump
Water table
Lake
Infiltration
Infiltration
Unconfined aquifer
Less permeable material such as clay
Confined aquifer
Confining impermeable rock layer
Fig. 11-3, p. 239
8
Use of Water Resources
  • Runoff use about 54
  • Freshwater use
  • US freshwater resources
  • Domestic, agricultural, and industrial use

9
Annual Precipitation and Water-deficit Regions of
the Continental US
Fig. 11-4a, p. 240
10
Annual Precipitation and Water-deficit Regions of
the Continental US
Average annual precipitation (centimeters)
Less than 41
81-22
More than 122
41-81
Fig. 11-4a, p. 240
11
Annual Precipitation and Water-deficit Regions of
the Continental US
Acute shortage
Shortage
Adequate supply
Metropolitan regions with population greater than
1 million
Fig. 11-4b, p. 240
12
Water Hot Spots in Western States
Wash.
N.D.
Montana
Oregon
S.D.
Idaho
Wyoming
Neb.
Nevada
Colo.
Utah
Kansas
California
Oak.
N.M.
Texas
Highly likely conflict potential
Substantial conflict potential
Moderate conflict potential
Unmet rural water needs
Fig. 11-5, p. 240
13
Freshwater Shortages
  • Causes of water scarcity dry climate and too
    many people
  • Stresses on worlds major river systems
  • 1 of 6 people have no regular access to clean
    water
  • Poverty hinders access to water
  • Hydrological poverty

14
Stress on Worlds River Basins
Europe
North America
Asia
Africa
South America
Australia
Stress
High
None
Fig. 11-6, p. 241
15
Hydrological Poverty
Fig. 11-7, p. 241
16
Politics and Ethics of Water
  • Who should pay for the water?
  • Public or private ownership

17
Increasing Freshwater Supplies
  • Dams and reservoirs
  • Extracting groundwater
  • Desalination
  • Reducing water waste
  • Importing food
  • Importing water
  • Catching precipitation

18
Tradeoffs of Large Dams and Reservoirs
Large losses of water through evaporation
Flooded land destroys forests or cropland
and displaces people
Downstream cropland and estuaries are deprived of
nutrient-rich silt
Migration and spawning of some fish are disrupted
Provides water for year-round irrigation
of cropland
Reservoir is useful for recreation and fishing
Can produce cheap electricity (hydropower)
Downstream flooding is reduced
Fig. 11-8, p. 243
19
Ecological Services of Rivers
N a t u r a l C a p i t a l
Ecological Services of Rivers
Deliver nutrients to sea to help
sustain coastal fisheries Deposit silt that
maintains deltas Purify water Renew and
renourish wetlands Provide habitats for
wildlife
Fig. 11-9, p. 243
20
California Water Project and Central Arizona
Project
CALIFORNIA
NEVADA
Shasta Lake
UTAH
Oroville Dam and Reservoir
Sacramento River
Lake Tahoe
Feather River
North Bay Aqueduct
Sacramento
San Francisco
Hoover Dam and Reservoir (Lake Mead)
South Bay Aqueduct
Fresno
San Joaquin Valley
Colorado River
San Luis Dam and Reservoir
Los Angeles Aqueduct
California Aqueduct
ARIZONA
Colorado River Aqueduct
Santa Barbara
Central Arizona Project
Los Angeles
Phoenix
Salton Sea
San Diego
Tucson
Fig. 11-10, p. 244
MEXICO
21
Aral Sea Disaster
  • Large-scale water transfers in dry central Asia
  • Salinity
  • Wetland destruction and wildlife
  • Fish extinctions and fishing
  • Wind-blown salt
  • Water pollution
  • Climatic changes
  • Restoration efforts

22
Shrinking Aral Sea
Fig. 11-11, p. 245
23
Stranded Ship at the Aral Sea
Fig. 11-12, p. 245
24
Tradeoffs of Withdrawing Groundwater
Trade-Offs
Withdrawing Groundwater
Advantages
Disadvantages
Good source of water for drinking and
irrigation Available year-round Exists almost
everywhere Renewable if not over- pumped or
contaminated No evaporation losses Cheaper to
extract than most surface waters
Aquifier depletion from over- pumping Sinking of
land (subsidence) when water removed Polluted
aquifiers unusable for decades or
centuries Saltwater intrusion into drinking
water supplies near coastal areas Reduced water
flows into streams, lakes, estuaries, and
wetlands Increased cost, energy use, and
contamination from deeper wells
Fig. 11-13, p. 246
25
Aquifer Depletion
Groundwater Overdrafts
High
Moderate
Minor or none
Fig. 11-14, p. 246
26
Saltwater Intrusion into Coastal Water Wells
Well contaminated with saltwater
Major irrigation well
Water table
Sea Level
Saltwater
Fresh groundwater aquifer
Seafloor
Interface
Saltwater Intrusion
Interface
Normal Interface
Fig. 11-15, p. 247
27
Groundwater Depletion
Solutions
Groundwater Depletion
Prevention
Control
Waste less water Subsidize water conservation Ba
n new wells in aquifiers near surface
waters Buy and retire ground- water withdrawal
rights in critical areas Do not grow
water- intensive crops in dry areas Reduce
birth rates
Raise price of water to discourage
waste Tax water pumped from Wells near
surface water Set and enforce minimum
stream flow levels
Fig. 11-16, p. 247
28
Desalination
  • Removal of salts from ocean or brackish waters to
    produce useable water
  • Distillation method
  • Reverse osmosis method
  • Used in 120 countries
  • Major problems high cost and a lot of brine
    wastes
  • Research is needed

29
Reducing Water Waste
  • Benefits of water conservation
  • Reduce leakage and save water
  • Water prices, government subsidies, and waste
  • Improve irrigation
  • Using less water in homes and businesses

30
Major Types of Irrigation Systems
Drip Irrigation (efficiency 90-95) Above- or
below-ground pipes or tubes deliver water to
individual plant roots.
Gravity Flow (efficiency 60 and 80 with surge
valves) Water usually comes from an aqueduct
system or a nearby river.
Center Pivot (efficiency 80 with low-pressure
sprinkler and 9095 with LEPA sprinkler) Water
usually pumped from underground and sprayed from
mobile boom with sprinklers.
Fig. 11-17, p. 249
31
Reducing Irrigation Water Waste
Solutions
Reducing Irrigation Water Waste
  • Lining canals bring water to irrigation ditches
  • Leveling fields with lasers
  • Irrigating at night to reduce evaporation
  • Using soil and satellite sensorsand computer
    systems to monitor soil moisture and add water
    only when necessary
  • Polyculture
  • Organic Farming
  • Growing water-efficient crops using
    drought-resistant and salt tolerant crops
    varieties
  • Irrigating with treated urban waste water
  • Importing water-intensive crops and meat

Fig. 11-18, p. 250
32
Reducing Water Waste
Solutions
Reducing Water Waste
  • Redesign manufacturing processes
  • Landscape yards with plants that require little
    water
  • Use drip irrigation
  • Fix water leaks
  • Use water meters and charge for all municipal
    water use
  • Use waterless composting toilets
  • Require water conservation in water-short cities
  • Use water-saving toilets, showerheads, and
    front-loading clothes washers
  • Collect and reuse household water to irrigate
    lawns and nonedible plants
  • Purify and reuse water for houses, apartments,
    and office buildings

Fig. 11-19, p. 250
33
Using Water More Sustainably
  • Blue revolution
  • Cut waste
  • Raise water prices
  • Drier waste treatment
  • Preserve forests
  • Slow population growth

34
Sustainable Water Use
Solutions
Sustainable Water Use
  • Not depleting aquifers
  • Preserving ecological health of aquatic systems
  • Preserving water quality
  • Integrated watershed management
  • Agreements among regions and countries sharing
    surface water resources
  • Outside party mediation of water disputes between
    nations
  • Marketing of water rights
  • Raising water prices
  • Wasting less water
  • Decreasing government subsides for supplying
    water
  • Increasing government subsides for reducing water
    waste
  • Slowing population growth

Fig. 11-20, p. 251
35
What Can We Do?
What Can You Do?
Water Use and Waste
  • Use water-saving toilets, showerheads, and faucet
    aerators
  • Shower instead of taking baths, and take short
    showers.
  • Repair water leaks.
  • Turn off sink faucets while brushing teeth,
    shaving, or washing.
  • Wash only full loads of clothes or use the lowest
    possible water-level setting for smaller loads.
  • Wash a car from a bucket of soapy water, and use
    the hose for rinsing only.
  • If you use a commercial car wash, try to find one
    that recycles its water.
  • Replace your lawn with native plants that need
    little if any watering.
  • Water lawns and garden in the early morning or
    evening.
  • Use drip irrigation and mulch for gardens and
    flowerbeds.
  • Use recycled (gray) water for watering lawns and
    houseplants and for washing cars.

Fig. 11-21, p. 251
36
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

37
Dangers of Floodplains and Floods
  • Deadly and destructive
  • Human activities worsen floods
  • Failing dams and water diversion
  • Bangladesh

38
Before and During a Flood in St. Louis, Missouri
Fig. 11-22, p. 252
39
Flooding After Deforestation of a Hillside
Forested Hillside
Oxygen released by vegetation
Diverse ecological habitat
Evapotranspiration
Trees reduce soil erosion from heavy rain and wind
Agricultural land
Steady river flow
Vegetation releases water slowly and reduces
flooding
Leaf litter improves soil fertility
Tree roots stabilize soil and aid water flow
Fig. 11-23a, p. 253
40
Flooding After Deforestation of a Hillside
After Deforestation
Tree plantation
Evapotranspiration decreases
Roads destabilize hillsides
Ranching accelerates soil erosion by water and
wind
Winds remove fragile topsoil
Agriculture land is flooded and silted up
Gullies and landslides
Heavy rain leaches nutrients from soil and erodes
topsoil
Rapid runoff causes flooding
Silt from erosion blocks rivers and reservoirs
and causes flooding downstream
Fig. 11-23b, p. 253
41
Table 11-1, p. 254
42
Reducing Flood Risks
  • Channelization
  • Levees (floodwalls)
  • Dams
  • Protect and restore wetlands
  • Identify and manage flood-prone areas
  • Precautionary approach

43
Water Pollution Types, Effects, and Sources
  • What is water pollution?
  • Major types of pollutants, sources and effects
    (Table 11-1, p. 254)
  • Point and nonpoint sources
  • Is the water safe to drink?

44
Polluted Streams
  • Factors influencing stream recovery from
    pollution
  • Oxygen sag curve
  • Importance of wastewater treatment plants
  • Improvements in quality of US streams
  • Cuyahoga River of Ohio
  • Effect of regulations in US
  • Pressures from US citizen groups
  • Problems with nonpoint, accidental and illegal
    releases
  • Problems in developing countries

45
Pollution in Streams
Normal clean water organisms (trout, perch,
bass, mayfly, stonefly)
Trash fish (carp, gar, leeches)
Fish absent, fungi, sludge worms, bacteria (anaero
bic)
Trash fish (carp, gar, leeches)
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. 11-24, p. 256
46
Lake Pollution
  • Dilution less effective than with streams
  • Stratification in lakes and relatively little
    flow hinder rapid dilution of pollutants
  • Lakes more vulnerable to pollutants than streams
  • How pollutants enter lakes
  • Eutrophication causes and effects
  • Oligotrophic and eutrophic lakes
  • Cultural eutrophication
  • Preventing or removing eutrophication

47
Oligotrophic and Eutrophic Lakes
Fig. 11-25, p. 257
48
Groundwater Pollution Causes and Persistence
  • Sources of groundwater pollution
  • Slow flowing slow dilution and dispersion
  • Consequences of lower dissolved oxygen
  • Fewer bacteria to decompose wastes
  • Cooler temperatures slow down chemical reactions
  • Degradable and nondegradable wastes in
    groundwater

49
Groundwater Pollution
Polluted air
Hazardous waste injection well
Pesticides and fertilizers
De-icing road salt
Coal strip mine runoff
Buried gasoline and solvent tank
Pumping well
Gasoline station
Water pumping well
Cesspool septic tank
Waste lagoon
Sewer
Landfill
Leakage from faulty casing
Accidental spills
Discharge
Unconfined freshwater aquifer
Confined aquifer
Confined freshwater aquifer
Groundwater flow
Fig. 11-26, p. 258
50
Extent of Groundwater Pollution
  • Not much is known about groundwater pollution
  • Organic contaminants, including fuel leaks
  • Arsenic
  • Protecting groundwater Prevention is best

51
Preventing and Cleaning Up Pollution in
Groundwater
Solutions
Groundwater Pollution
Prevention
Cleanup
Find substitutes for toxic chemicals
Pump to surface, clean, and return to aquifer
(very expensive)
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
Pump nanoparticles of inorganic compounds to
remove pollutants (may be the cheapest, easiest,
and most effective method but is still being
developed)
Store harmful liquids in aboveground tanks with
leak detection and collection systems
Fig. 11-27, p. 259
52
Ocean Pollution
  • How much pollution can oceans tolerate?
  • Some pollutants degrade and dilute in oceans
  • Ocean dumping controversies

53
Coastal Water Pollution
Urban sprawl Bacteria and viruses from sewers and
septic tanks contaminate shellfish beds and close
beaches runoff of fertilization from lawns adds
nitrogen and phosphorus.
Cities Toxic metals and oil from streets
and parking lots pollute waters sewage adds
nitrogen and phosphorus.
Industry Nitrogen oxides from autos and
smokestacks toxic chemicals, and heavy metals in
effluents flow into bays and estuaries.
Construction sites Sediments are washed into
waterways, choking fish and plants,
clouding waters, and blocking sunlight.
Farms Run off 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.
Healthy zone Clear, oxygen-rich waters promote
growth of plankton and sea grasses, and support
fish.
Oxygen-depleted zone Sedimentation and algae
overgrowth reduce sunlight, kill beneficial sea
grasses, use up oxygen, and degrade habitat.
Fig. 11-28, p. 260
54
Oxygen-depleted Water in the Gulf of Mexico
Mississippi River Basin
Ohio River
Mississippi River
Missouri River
LOUISIANA
Mississippi River
Depleted Oxygen
Gulf of Mexico
Fig. 11-29, p. 261
55
Chesapeake Bay
  • Largest US estuary
  • Pollution sink
  • Oxygen depletion
  • Chesapeake Bay Program

Fig. 11-30, p. 261
56
Chesapeake Bay
Cooperstown
NEW YORK
PENNSYLVANIA
ATLANTIC OCEAN
Harrisburg
NEW JERSEY
MARYLAND
Baltimore
WEST VIRGINIA
Washington
DELAWARE
Richmond
VIRGINIA
Chesapeake Bay
Norfolk
Drainage basin
Low concentrations of oxygen
No oxygen
Fig. 11-30, p. 261
57
Effects of Oil on Ocean Life
  • Crude and refined petroleum
  • Tanker accidents and blowouts
  • Exxon Valdez
  • Volatile hydrocarbons kill larvae
  • Tar-like globs coat birds and marine mammals
  • Oil destroys insulation and buoyancy
  • Heavy oil sinks and kills bottom organisms
  • Coral reefs die
  • Slow recovery
  • Oil slicks ruin beaches

58
Preventing and Cleaning Up Pollution in Coastal
Waters
Solutions
Coastal Water Pollution
Prevention
Cleanup
Reduce input of toxic pollutants
Improve oil-spill cleanup capabilities
Separate sewage and storm lines
Ban dumping of wastes and sewage by maritime and
cruise ships in coastal waters
Sprinkle nanoparticles over an oil or sewage
spill to dissolve the oil or sewage without
creating harmful byproducts (still under
development)
Ban ocean dumping of sludge and hazardous dredged
material
Protect sensitive areas from development, oil
drilling, and oil shipping
Require at least secondary treatment of coastal
sewage
Regulate coastal development
Use wetlands, solar-aquatic, or other methods to
treat sewage
Recycle used oil
Require double hulls for oil tankers
Fig. 11-31, p. 263
59
Preventing Nonpoint Source Pollution
  • Mostly agricultural wastes
  • Use vegetation to reduce soil erosion
  • Reduce fertilizer use
  • Use plant buffer zones around fields
  • Integrated pest management Only use pesticides
    when necessary
  • Use plant buffers around animal feedlots
  • Keep feedlots away from slopes, surface water and
    flood zones

60
Laws for Reducing Point Source Pollution
  • Clean Water Act
  • Water Quality Act

61
Sewage Treatment Systems
  • Sewage treatment in rural and suburban areas
  • Septic tanks
  • Primary (physical) sewage treatment
  • Secondary (biological) sewage treatment
  • Urban sewage treatment (Clean Water Act)
  • Sewage treatment facilities in many cities fail
    to meet federal standards
  • Bleaching and disinfection
  • Disinfectants chlorine, ozone, and ultraviolet
    radiation

62
Typical Septic Tank System
Septic tank with manhole (for cleanout)
Household wastewater
Nonperforated pipe
Distribution box (optional)
Gravel or crushed stone
Drain field
Vent pipe
Perforated pipe
Fig. 11-32, p. 264
63
Primary and Secondary Sewage Treatment
Primary
Secondary
Chlorine disinfection tank
Bar screen
Grit chamber
Settling tank
Aeration tank
Settling tank
To river, lake, or ocean
Sludge
Activated sludge
(kills bacteria)
Raw sewage from sewers
Air pump
Sludge digester
Disposed of in landfill or ocean or applied to
cropland, pasture, or rangeland
Sludge drying bed
Fig. 11-33, p. 265
64
Improving Sewage Treatment
  • Systems that exclude hazardous wastes
  • Non-hazardous substitutes
  • Composting toilet systems
  • Working with nature to treat sewage
  • Using wetlands to treat sewage

65
Ecological Wastewater Treatment
Fig. 11-34, p. 265
66
Should the Clean Water Act be Strengthened?
  • Yes environmentalists
  • No farmers, libertarians, manufacturers, and
    developers
  • State and local officials want more discretion

67
Drinking Water Quality
  • Purification of urban drinking water
  • Purification of drinking water in developing
    countries
  • Bottled water

68
Reducing Water Pollution
Solutions
Water Pollution
  • Prevent groundwater contamination
  • Greatly reduce nonpoint runoff
  • Reuse treated wastewater for irrigation
  • Find substitutes for toxic pollutants
  • Work with nature to treat sewage
  • Practice four R's of resource use (refuse,
    reduce, recycle, reuse)
  • Reduce resource waste
  • Reduce air pollution
  • Reduce poverty
  • Reduce birth rates

Fig. 11-35, p. 267
69
What Can We Do?
What Can You Do?
Water Pollution
  • Fertilize your garden and yard plants with manure
    or compost instead of commercial inorganic
    fertilizer.
  • Minimize your use of pesticides.
  • Never apply fertilizer or pesticides near a body
    of water.
  • Grow or buy organic foods.
  • Compost your food wastes.
  • Do not use water fresheners in toilets.
  • Do not flush unwanted medicines down the toilet.
  • Do not pour pesticides, paints, solvents, oil,
    antifreeze, or other products containing harmful
    chemicals down the drain or onto the ground.

Fig. 11-36, p. 268
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