Water resources, pollution and management.

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Water resources, pollution and management.

• How much of water is freshwater?
• Can freshwater supply be guaranteed?
• How can we ensure continuous supply?

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How much freshwater is available?

• 70 of the earth's surface is covered with water
  but only a fraction is available for human use as
  freshwater
• 97.5 of earths surface water is saltwater found
  in oceans and seas.
• 2.5 of the remaining is Freshwater but 68.9 of
  it is locked up in ice caps or glaciers, 30.8 is
  groundwater and 0.3 of the water is contained in
  lakes and ponds.

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Global freshwater distribution glaciers and ice
caps, km31

• Antarctica
• Greenland
• North America
• Asia
• Europe
• South America
• Australia
• Africa

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Global freshwater distribution wetlands, lakes
and rivers2

• 1. Asia - 30,622 km3
• 2. Africa - 31,776 km3
• 3. North America - 27,003 km3
• 4. South America - 3,431 km3
• 5. Europe - 2,529 km3
• 6. Australia - 221 km3

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Predicted water scarcity in 2025
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Global use and waste of water
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What are the causes of recent shortages in global
water supplies?

• Global warming and irregular precipitation
• Drier climates and droughts
• Increases in human population
• Expansion in industrial uses of water
• Expanded urban use and waste of water
• Water pollution
• Unequal distribution of freshwater
• Expanded agricultural uses - irrigation

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Chemical composition of water

• A covalent chemical bond consists of two
  atoms that share a pair of electrons between
  them. In the water molecule H2O, the single
  electron of each H is shared with one of the six
  outer-shell electrons of the oxygen, leaving four
  electrons which are organized into two
  non-bonding pairs.

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Chemical structures of liquid water and ice
crystals

• Three-dimensional views of a typical
  structure of
• 1. liquid water.. and
• 2. ice molecules

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Recommended basic daily domestic water
requirement per person (litres)

• Drinking 5 litres of water per person
• Sanitation 20
• Bathing 15
• Cooking 10
• -------------------------------------------
  ------
• TOTAL 50 litres of water per person

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Water needs of the human body

• principal component of blood.
• transportation medium for substances such as
  vitamins, hormones and enzymes
• a medium for getting rid of waste in the body
  (e.g. sweat and urine).
• a 12 loss of the 50 liters (110lbs) of water in
  an adult body results in death.
• dissolves minerals and vitamins for easy
  absorption by the human body.

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Human uses of water

• Water withdrawal removes water from a supply
  stream, use it, and return it to the supply
  chain.
• Consumptive uses removes water from a supply
  stream (e.g. domestic uses such as cooking,
  washing, bathing) but do not return it.
• Non-consumptive uses removes water from a
  supply stream (industry, municipal uses,
  irrigation) but do not return it.

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Most freshwater is beyond reach

• Most freshwater is beyond reach.
• Victorian Falls on River Zambezi in Africa and
  ...
• A waterfall at Wli in Ghana, West Africa

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Domestic uses of water

• domestic uses of water include washing,
  cooking bathing, gardening, cleaning etc

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Domestic uses of water

• Water for domestic uses in the Savanna regions
  of Africa

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Human uses of water

• Humans and other species cannot exist without
  water indeed.
• An Iraqi man drinks water as bombs explode
  around during the 2003 US war with Iraq.

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Religious uses of water

• Water for healing, cleansing and baptism

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Water for Leisure and relaxation

• I couldn't resist the swans sitting
  contentedly within a couple of yards of the
  fisherman. It typifies the multi-purpose nature
  of waterways as habitat, transport route,
  leisure resource and, of course, a fine place to
  while away time.

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Water for the animals

• Washing an elephant in a river in Sri Lanka

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Water for the animals

• A trip in the Tenere desert in the Tuareg
  region in Niger, Africa.
• A woman stopping to find water for her donkeys

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Water a habitat for many species

• Feeding Caribbean reef sharks with fish from
  a canister wearing a metallic protection suit

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Water for Irrigation agriculture

• This is the All American Canal in Yuma,
  Arizona USA. This is the canal that allowed the
  Colorado River to transform the desert in Yuma
  and the Imperial Valley of California into one of
  the worlds biggest food producing areas!

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Water pollution1

• Water pollution refers to any contamination of
  water that lessens its value to humans and nature
• 1. Point pollution source
• 2. Non-point pollution sources
• Farmlands - pesticides, manure, fertilizer
• Grazing lands - animal wastes
• Stream banks - sediments
• Abandoned mines - acid drainage from coal mines
• Roadside deicing - salt, lead and sediments

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Types of surface water pollution

• Sediment pollution banks of rivers
• Nutrient pollution euthrophication in lakes and
  ponds
• Thermal pollution in shallow seas and streams
• Toxic chemicals pollution factory outlets
• Sewage from urban areas

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Problems related to water supplies

• Drought and famines loss of lives
• Floods destruction of property and loss of
  lives
• Overdraft of surface water disappearance of
  lakes, ponds, streams
• Overdraft of groundwater diminishing surface
  water, land subsidence, saltwater intrusion into
  coastal soils.

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Increasing Freshwater supplies

• Building dams and reservoirs
• Bring surface water from another area
• Withdraw groundwater wells and springs
• Convert saltwater into freshwater
• Improve water use efficiency
• Conserve water
• Reclaim sewage water for reuse
• Rain-making through cloud seeding
• Harvesting ice bergs

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The Hydrological Cycle
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Groundwater reserves km3

• 1. Asia 7,800,000
• 2. Africa 5,500,000
• 3. North America - 4,300,000
• 4. South America 3,000,000
• 5. Europe 1,600,000
• 6. Australia 1,200,000

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Sources of groundwater pollution

• Seepage from landfills
• Septic tanks
• Leaks from underground gasoline tanks
• Dissolved chemicals from farms
• Run-off and seepage from industrial waste dumps

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What you can do to preserve water