Fresh & Salt Water Systems

Earth is called the ‘blue planet”

because 74% of the surface is covered

by water.

The hydrosphere is the area of Earth and its atmosphere where water (and life) is

present.

Water in the World97% is salty… only 3% is fresh… and most of that is frozen!

In reality only 0.3% of the Earth’s water is useable by

humans!

What do you use water for?

Who has the water?

• four countries hold almost half of the Earth’s renewable supply of freshwater: * Brazil 18% * Canada 9% * China 9% * United States 8%

• most of our water is used to feed us!– 73% Agricultural Use– 22% Industrial Use– 5% Domestic Use (including drinking)

Water in Canada

• The Pacific watershed lies west of the Continental Divide in the Canadian Rockies.

• Canada has 5 major watersheds (drainage basins)

Water in Alberta

• Alberta has just over 2% of Canada’s water supply.

• 80% of our water is in the north… 80% of our water use is in the south.Beaver

River Basin

North Saskatchewan River Basin

South Saskatchewan River Basin

Milk River Basin

To Arctic

To Hudson’s Bay

Hay River Basin

Peace/Slave River Basin

Athabasca River Basin

To Gulf of Mexico

In Alberta…• 97.5 of our drinking water comes from surface

sources• water is often stored in reservoirs for future use

• 2 billion people do not have access to sanitation systems

• 1 billion people do not have access to safe drinking water

• 3 million people die every year from lack of clean water for drinking, cleaning and irrigation

• ¼ of the world population gets its water from the aquifers located under ground … but groundwater supplies takes a long time to replenish!

Did you know?

Would you drink this water?

• life on Earth depends on the quality of water contained in the hydrosphere

• freshwater is not just H2O → it contains:– dissolved compounds such as salts, phosphorous and

other minerals– dissolved gases– suspended particles (of earth)– living organisms adapted to local environments

• saltwater also contains salt – 3.5% more salinity than freshwater

Indicators of Water Quality

• dissolved oxygen– must be between 5 – 8 ppm to sustain life– water movement increases dissolved oxygen– cold water holds more dissolved gases (including

oxygen)– increasing temperature or suspended sediments in

water will reduce the dissolved oxygen level

• acidity– pH of about 5.6 is normal for rain and snow– if water gets too acidic (pH below 4.5) fish will die– acid rain or runoff with lots of fertilizers will make the

water more acidic

How does your water taste?

smell? look?

How does your water taste?

smell? look?

• heavy metals– these are dense metals which can accumulate in the

environment and cause disease in organisms– 3 most common are lead, mercury & cadmium

• nitrogen and phosphorous– chemicals from fertilizers and sewage– promote algae growth, increased bacteria and

decreased dissolved oxygen concentration

• pesticides– chemicals use to kill weeds or insects– can build up in the food chain and damage

populations of plants and animals– often runoff farmers fields or lawns and end up in

waterways

• salts - many organisms cannot tolerate large concentrations of salt

• polychlorinated byphenyls (PCBs)– still linger in our environment even though they were

banned in 1977– can cause skin conditions and liver damage

• biological markers are microscopic organisms present in our water– healthy populations of species such as flatworms,

clams and insects can indicate good water quality– organisms such as E. coli can indicate poor water

quality

Cleaning Water

• water is purified in nature

by the hydrological cycle

→ when water evaporates it leaves behind dissolved compounds… and then rain water is of better quality

Did you know that a

litre of oil costs

about 40 cents …

while a litre of water

costs about $3!

Did you know that a

litre of oil costs

about 40 cents …

while a litre of water

costs about $3!

Producing Freshwater

• distillation– water is boiled in a container– evaporating water leaves impurities behind– the resulting water vapor is collected, allowed

to condense, producing clean distilled water

• reverse osmosis– pressurized salt water is pushed through a

semi permeable membrane which filters out the salt

Water Softening

• hard (fresh) water is common in many areas… including Calgary

• hard water has lots of minerals in it, such as calcium and magnesium

• hard water limits the foaming action of soap/detergent and leaves a film on your skin

• soft water removes some of these minerals