The Nature of Water Resources


How does water move?
The water cycle (or hydrologic cycle) is the continuous circulation of water within the Earth's hydrosphere, and is driven by solar radiation. As water moves through the cycle, it changes state between liquid, solid, and gas phases.

As the saying goes ... "water, water, everywhere." Well, how much water is there; where is the water; how does it move around?


How Much Water?

The amount of water on Earth remains about the same from one year to the next, at about 70% of the earth’s surface. However, most of the water on Earth is not available for human use.


Of global water sources, 97.47% is saltwater and 2.53% is freshwater. Of the freshwater portion, most is found in ice (69.56%), while the remaining portions are found as deep groundwater (30.06%), or in surface waters (rivers, lakes and shallow groundwater) (0.389%). This means the available freshwater (not frozen or underground) is 0.01% of the total water on the planet.


Where is the Water?


Canada ranks fourth worldwide as having the most freshwater behind Russia, China and Brazil. Almost 9% of Canada's total area is covered by freshwater. Canada has more lake area than any other country in the world with an estimated 2 million lakes, covering approximately 7.6% of our land area.

The Great Lakes, Canada’s most important freshwater source, are the largest system of fresh, surface water on earth, containing roughly 20% of the world’s freshwater supply (Environment Canada 1995). Despite its large size, the Great Lakes Basin does not represent an inexhaustible supply of freshwater. The Great Lakes have roughly only 1% of its waters renewed each year by snowmelt and rain. This renewable volume is what is left each year for human use, which needs to be used in a sustainable manner, in order to protect water availability for future generations.


Related Links

To learn more about the nature of water, visit the following links:


Water Use
In 2004, Canadians were ranked one of the largest users of water in the world, using 343 litres of water per day.

Learn more about Water Use in Ontario.


A watershed is a discrete ecosystem composed of the land and waters in an area that is drained by a watercourse and its tributaries. There are three primary watersheds in the province of Ontario. Learn more about Watersheds


Water Sources
Surface waters are visible sources of water best represented by wetlands, lakes and rivers and intermittent watercourses. Find out more about Lakes & Rivers


Groundwater refers to the water under the earth in the zone where all the pores in the containing material are saturated.  Learn more about groundwater.

Water Levels and Flows
Stream flow and water level data is collected at hydrometric gauging stations to monitor the current water resource conditions in Ontario. 
Learn more about Water Levels & Flows