Water Resources

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  1. Earth/water facts:
    • 71% of the earth's surface is covered with water
    • 97.5% is found as salt water in seas and oceans
    • Only 2.5% of Earth's water is freshwater
    • 70% of fresh water is locked in glaciers are polar ice caps- unavailable
    • Much of remainder is soil "moisture" or locked in deep aquifers unavailable
    • Less than 1% is freshwater in rivers, lakes, and streams
  2. Available Freshwater for Humans
  3. More Water Facts
    • Human body is 65% H2O
    • Humans require between 1-3 liters of fresh water per day to drink
    • 50 liters per day is considered the bare minimum a human needs daily
    • Avg. person in US uses >500 liters/day
  4. Water Consumption
    • Agriculture- largest user of water (60%)
    • Industry (15%)
    • Housholds (25%)
  5. Groundwater
    • Makes up 20% of worlds fresh water suply
    • Usually cleaner and purer than surface water sources
    • Soil filters out bacteria and other contaminants
    • Dependable supplies because there is no evaporation
    • Now threatened by pollution and overuse
  6. Groundwater Pollution
    • Can be chemical, biological, or radiological
    • Amendments to the Safe Drinking Water Act of 1986 cover contaminants in public water systems, but not the approximately 12 million private wells in the US
    • 58% of waterborne disease outbreaks between 1971-2006 traced to microbially contaminated groundwater
  7. Groundwater Pollution
    • Waste storage or treatment facilities
    • Chemcial Industrial Activity
    • Septic systems
    • Sweers, oil pipleines, accidental spills
    • Irrigation, mine drainage, farm chemicals, manures, substances applied to roads
  8. Wars over Water?
    • Water demand is increasing with population growth, but water supply is finites
    • Darfur- 400,000 deaths (farmers vs. nomads)
    • Gaza- More than 1 million share one aquifer
  9. Developing World Differences
    1.5 billion people still access to safe drinking water
  10. South America
    • Amazin basin in S. America contains 20% of Earths freshwater
    • 50-90% of water lost through leaky pipes
    • Waste and Population; Increasing populations means cities must rely on sources much farther away
    • MOre than 140 million people have no safe drinking water in their homes
    • Private for Profit Companies- three companies now provide water for 300 million people. Outrageous rates, reduced water quality, huge profits
    • In bolivia Bechtel Crop busted up rain catchers, claiming they now owned rain
    • Thousands rioted, and the new Bolivian govt. canncelled Bechtels contract
    • Bechtel now owns the water infrastructure and distribution contract for post war Iraq
  11. Mega Dams
    • Benefits: Irrigate crops, control flooding, cheap clean power, recreations
    • Consequences: Alter ecosystems, change fish stocks, chinese river dolphins, loss of high quality agricultural land, loss of small towns, resettlement of people, loss of archeological sits/fossils
  12. Clean Water Act, 1972
    • No one has the right to pollute
    • Pollution continues due to technological limits and economic blackmail
  13. US Pollution Facts
    • Too polluted for swimming or fishing
    • 40% of rivers
    • 46% of lakes
    • 2/3 of all estuaries
    • In any given year, about 25% of beaches in the US are under advisories or are closed at least one time because of water pollution
  14. Most Polluted US rivers
    • Mississippi River
    • Ohio River
    • Tennessee River
    • Ward Cove
    • Savannah River
    • Delaware River
    • Thanmes River, CT
  15. Types of water pollution
    • Point Source: Industry
    • Non-Point source:
    • Agriculture
    • Construction
    • Urban street runoff/country dwellers
    • acid mine drainage
    • airborne pollutants
  16. Wastewater treatment
    • POTW (Publicly owned treatment works)
    • serve 70% of the US population
    • Prevents Disease
    • Water Re-Usage
    • In average US community each person uses 100 gallons water/day/person
  17. Sewer Treatment (Primary Treatment:)
    • Removal of large debris
    • Aeration
    • Sedimentation and sludge removal
  18. Sewer Treatment: Secondary
    • Microorganisms added to decompose wastes
    • Disinfection (chlorine)
    • Dechlorination
  19. Drinking Water
    • Oregon: 75% citizens get their drinking water from public water systems
    • US: 53% surface water, 46% groudnwater
    • Surface Water: Rivers, lakes, reservoirs
    • Ground water: pumped from wells drilled into aquifers
  20. Bottled Water
    • Advantages:
    • Only alternative for contaminated wells
    • Safe supply in case of emergency
    • Disadvantages:
    • Expensive (10,000X higher)
    • Consumes ernergy and resources
    • Potentially dangerous (75% of bottled water not regulated)
Card Set:
Water Resources
2012-03-18 20:13:03
Environmental Health

Bottle Caps and booty.
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