Water

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Water
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Abundance/location

• 97.5 by volume is found in the sea water (3.5
  salinity)
• 2.5 is fresh water
• 1.97 in ice caps
• 0.5 in ground water
• 0.03 in rivers, lakes, soil and atmosphere
• Potable usable water

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Chemistry

• H2O dihydrogen monoxide
• Polar Positively (H) and negatively (O) charged
  ends
• - results in hydrogen bonding between molecules

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• Cohesion and Adhesion water sticking to itself
  (co) and to other things (ad)
• Main importance Transpiration movement of
  water up the xylem in plants

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• Less dense as a solid
• water is densest at 4oC
• lower temperatures causes the hydrogen bonds get
  stronger and spread molecules apart making it
  less dense Ice Floats
• maintains aquatic biomes in winter

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• ICE Liquid Water Gas

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• High Specific Heat
• heats and cools slowly
• Climate Control regulates coastal temperatures,
  ocean currents, wind patterns
• Evaporative Cooling as water evaporates it
  removes heat

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• Solvent dissolves substances that are charged
  makes them more available for nutrient uptake in
  plants and animals

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Hydrologic Cycle

• Processes
• Evaporation
• Transpiration plants
• Precipitation rain, snow, sleet, fog, dew
• Percolation movement of water through soil and
  rocks

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• Ground water water that has percolated until it
  reaches impenetrable rock
• flow rate a few millimeters to a few meters per
  day depending on the composition of the soil
• eventually flows into streams or rivers or is
  confined in an aquifer

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Aquifer underground reservoir

• Unconfined aquifer under layers of porous
• rock (sedimentary rock limestone, sandstone)
• - can be replenished by surface water
• - the upper level of the aquifer water table
• - if the level of the water table rises above the
  level of the ground pond or lake or stream

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• Confined (artesian) aquifer between layers of
  non-porous rock (morphological granite, marble)
• - recharged many miles away where the area above
  is porous

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• Wells drill down into the water table pressure
  of the water determines how many gallons of water
  the well will produce
• a dry well means the water table level has
  fallen below the depth of the well

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• Run-off water that does not percolate moves to
  streams and rivers
• - can carry away soil (erosion), plants,
  animals and chemicals
• Watershed drainage basin for a stream or river

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• Riparian Zone transition zone between land and a
  stream or river
• denoted by hydrophilic plants
• typically high biological diversity
• important for preventing soil erosion plant
  roots hold soil in place
• - helps control flow of rivers and streams by
  maintaining the integrity of the river or stream
  bank

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• Flood Plains areas where rivers and streams
  periodically overflow the banks of the river
  can deposit fertile soil from upstream
• Ex Fertile Crescent

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Flooding

• Humans contribute to flood deaths and damage by
  removing vegetation, living in the floodplains,
  through urbanization (highways, parking lots,
  etc.).

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How can we reduce flooding risks?

• Channelization (straightening and deepening
  streams) PAGE 305
• - reduces upstream flooding, increases upstream
  bank erosion and downstream flooding and
  deposition of sediment

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How can we reduce flooding risks?

• Building levees and dams
• - increases water's capacity for doing damage
  downstream
• Restoring wetlands absorb excess water

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• Instituting floodplain management maintaining
  vegetative areas, controlling and diverting
  run-off (collecting ponds near highways)

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• Underground Chattanooga

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• WATER USES
• How do we use the world's fresh water?
• 65 irrigate farm land (agriculture)
• 25 energy production
• 10 domestic and municipal use

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• PRODUCT GALLONS USED
• Car 100,000
• Ton of brown paper 82,000
• pound of cotton 2000
• pound of aluminum 1000
• pound of beef 800
• pound of rice 560
• pound of steel 25
• gallon of gasoline 70

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• KINDS OF WATER USE
• The use of water is usually grouped into 4 uses
  
• 1. domestic
• 2. agricultural
• 3. in stream use
• 4. industrial

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• Domestic water cleaned water from streams and
  rivers
• The typical family of 4
• 24 liters for drinking and cooking
• 72 liters for cleaning dishes
• 400 liters flushing toilets
• 320 liters bathing
• 152 liters for laundry
• 400 liters on lawns.
• TOTAL 300 liters per person per day.

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• The USA uses 338 billion gallons per day (1993)
  1400 gal/person/day.
• 10 is public tap water
• 11 by industry
• 38 to cool power supply company equipment
• 41 for agriculture.

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• Agricultural water is used mostly for irrigation.
  
• - crops and livestock
• Dams provide electricity and water
• interfere with the natural river systems
• slows rivers

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• Problems with irrigation. Salinization
• Water goes into the land and not out
• Natural salts go into the land causing it to get
  saltier.

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• reduces crop yields
• can dissolve traces of toxic materials in an
  irrigated field.
• Can lead to Desertification land becomes so
  salty, plants cannot grow in the soil even if it
  is wet

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• Instream Use
• - use of water in the stream
• - hydroelectric dams
• - cheap electricity and recreation
• changes ecosystem of river flowing to
  non-flowing
• - alters flow of stream
• - temperature changes affect oxygen levels in
  water
• - warm water low O2
• - cold water high O2
• - leads to changes in stream/river populations

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• Industrial Use of Water
• - mainly used to cool things by using the water
  to carry away heat
• - may lead to thermal pollution changes the
  temperature of the water which affects the
  organisms that live there
• most companies have a cooling channel to allow
  the water to cool before dumping into the river

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• Water Issues
• Too Little
• Causes of Freshwater Shortages
• Dry climate
• Drought
• Desiccation loss of water (dries up)
• Water Stress over use of water

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• How Can Water Supplies be Increased?
• Build dams and reservoirs
• - capture and store water from rain and melting
  snow then released as desired to produce elec.
  power, irrigate land, control flooding below the
  reservoir and provide water to towns
• - can reduce downstream flow to a trickle
  (Colorado River)
• - reduce biodiversity
• - fish ladders

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• Bring in surface water from another area
• Withdraw groundwater
• Desalination
• Distillation
• Reverse Osmosis
• Uses vast amount of electricity.
• Distribution of desalinated water is also costly
• Process produces large quantities of brine
  (contains high levels of salt and minerals)

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• Cloud Seeding
• Add chemicals to clouds to promote rain
• Legal issues over the ownership of water in
  clouds
• Tow massive icebergs to arid coastal areas.