water resources and water pollution

1. WATER RESOURCES AND
WATER POLLUTION
Prepares by-
Sushil Kumar Singh
B.Pharma (final year)

2. Water Resources
•Water
• Earth’s surface is covered by 71% water
• Essential for life – can survive only a few
days without water
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3. Supply of Water Resources
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Small fraction (.014%) is readily
available for human use

4. Water Cycle – continuously collected,
purified, recycled and distributed
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Evaporation and transpiration
Evaporation
Stream
Infiltration
Water tableInfiltration
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Less permeable material
such as clay Confirming permeable rock layer

5. Watershed
• A watershed describes the total area contributing
drainage to a stream or river
• May be applied to many scales
• A large watershed is made up of many
small watersheds
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6. Water sources
Surface runoff – 2/3 lost to floods and not available
for human use.
Reliable runoff = one third
• Amount of runoff that we can count on year to year
Groundwater
Zone of saturation
Water table – top of zone of saturation
Aquifer – water saturated layers of sand, gravel
or bedrock through which groundwater flows.
Recharge slow ~ 1 meter per year
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7. Use of Water Resources
Humans directly or indirectly use about 54% of
reliable runoff
Withdraw 34% of reliable runoff for:
Agriculture – 70%
Industry – 20%
Domestic – 10%
Leave 20% of runoff in streams for human use:
transport goods, dilute pollution, sustain fisheries
Could use up to 70-90% of the reliable runoff by
2025
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8. Too Little Water
• Problems in the
• West
• Dry climate
• Drought
• Desiccation
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Acute shortage
Adequate supply
Shortage
Metropolitan regions with
population greater than 1 million
US has plenty of water.
Much of it is in the wrong
place at the wrong time.
Most serious problems are
flooding, pollution,
occassional urban shortages

9. Too Much Water: Floods
• Natural phenomena
• Aggravated by human activities
• Rain on snow Living on floodplains
• Impervious surfaces
• Removal of vegetation
• Draining wetlands
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Floodplain
Levee Flood
wall
Dam
Reservoir

10. Deforestation and flooding
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11. Pollution Source terminology
• Point source = pollution comes from single, fixed, often
large identifiable sources
• smoke stacks
• discharge drains
• tanker spills
• Non-point source = pollution comes from dispersed
sources
• agricultural runoff
• street runoff
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12. Types of Water Pollution
• Sediment
• logging, roadbuilding, erosion
• Oxygen-demanding wastes
• human waste, storm sewers, runoff from agriculture, grazing and
logging, many others
• Nutrient enrichment = Eutrophication
• N, P from fertilizers, detergents
• leads to increased growth in aquatic systems, ultimately more non-
living organic matter
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13. BOD
• As micro-organisms decompose (through respiration)
organic matter, they use up all the available oxygen.
• Biological Oxygen Demand (BOD) Amount of oxygen
required to decay a certain amount of organic matter.
• If too much organic matter is added, the available oxygen
supplies will be used up.
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15. Eutrophication
Eutrophic – well-fed, high nutrient levels present in a lake
or river
Oligotrophic – poorly-fed, low nutrient levels
Water bodies can be naturally eutrophic or oligotrophic, but
can also be human-caused
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16. Types of Water Pollution (con’t)
 Disease-causing organisms
 from untreated sewage, runoff from feed lots
 Toxic chemicals
 pesticides, fertilizers, industrial chemicals
 Heavy metals
 lead, mercury
 Acids (to discuss later)
 Elevated temperatures = Thermal Pollution
 water is used for cooling purposes, then heated water is
returned to its original source
 any increase in temperature, even a few degrees, may
significantly alter some aquatic ecosystems.
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17. Groundwater Pollution
• Agricultural products
• Underground storage tanks
• Landfills
• Septic tanks
• Surface
impoundments
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18. Oil Spills
• Exxon Valdez released 42 million liters of oil in
Prince William Sound, contaminating 1500 km
of Alaska coastline in 1989
• Was the cleanup effective?
• Most marine oil pollution comes from non-point
sources:
• runoff from streets
• improper disposal of used oil
• discharge of oil-contaminated ballast water from
tankers
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19. Growth of population
• Supply & demand are in growing conflict – supply is
finite – water management driven by values and needs
• Increases demand/use of water
• Increases land use and changes vegetation and
permeability
• Increases demand for instream values – instream
flows are for people
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20. Water Rights
• Water collectively belongs to the public
• Cannot be owned by individuals
• Individuals or groups may be granted rights to use
water
• Legal authorization to use a predefined quantity of public water
for a designated purpose.
• Irrigation, domestic water supply, power generation
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21. Water Rights
• State law requires certain users of public waters to
receive approval from the state prior to using water.
• Any use of surface water which began after 1917
requires a water-right permit.
• Withdrawals of underground water from 1945 requires
a water-right permit.
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22. Thank You!
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