Hydrologic Cycle
What is the Hydrologic cycle?
From the beginning of time when water first appeared, it has been constant in quantity and continuously in motion. Little has been added or lost over the years. The same water molecules have been transferred time and time again from the oceans and the land surface into the atmosphere by evaporation, dropped on the land as precipitation, and transferred back to the sea by rivers and groundwater. This endless circulation is known as the "hydrologic cycle". At any instant, about 5 litres out of every 100 000 litres is in motion.
Over time, major cyclic changes in climatic processes have produced deserts and ice cover across entire continents. Today, regional short-term fluctuations in the order of days, months, or a few years in the hydrologic cycle result in droughts and floods.
The above information was provided courtesy of Environment Canada (Learn more by visiting their Aquatic Ecosystems pages at http://www.ec.gc.ca/water/en/nature/aqua/e_aqua.htm)
