the earth's formation over 4.5 billion years ago, no new water has
been created. The same amount of water has been continually filtered
and re-filtered, cycled and recycled by man and nature.
Life on earth began in water, and the existence of life on the "water
planet" is dependent upon the hydrocycle.
hydrologic cycle or "water cycle" continually replenishes this supply
through precipitation, runoff, percolation, evaporation, condensation,
and once again precipitation.
is our most precious resource. One cannot live without water. It constitutes
two thirds of our body weight and covers two thirds of the planet.
majority of the existing water is not fresh water, but sea or salt
water. Of the earth's 326 million cubic miles of water, only 3% is
water is truly a rare commodity.