Freshwater Resources
Introduction
Water covers nearly three-quarters of the earth's surface, mainly in oceans but also as rivers, lakes, snow and glaciers. Water is also found in the atmosphere and underground. Over 97% of the earth's water is salty with the remainder in various forms of freshwater.
Freshwater is defined as water that generally contains less than 1000 milligrams per litre of dissolved solids. Of the world's freshwater, about 99.9% is either found in glaciers and icefields, or is underground. However, the tiny percentage of freshwater we are most familiar with is that found either as surface water (lakes, rivers and wetlands), or which occurs in the atmosphere, or is found in the soil. According to some estimates, the quantity of groundwater in the earth would cover the entire surface of the globe to a depth of 120 metres. By contrast, the volume of surface water in lakes, rivers, reservoirs and swamps could be contained in a depth of about one quarter of a metre. Scientists estimate the world's freshwater at over one billion cubic kilometres.
Freshwater is basic to life: it supports plants and animals in almost all ecosystems, even those in deserts. Aquatic ecosystems are perhaps the most obvious evidence of the importance of freshwater: lakes, ponds, rivers, streams and wetlands support a wide variety of species and provide important ecological functions.
Freshwater is also a basic component of human society. Not only does freshwater support resources such as agriculture, fish and forests upon which society depends for food, clothing and shelter, but freshwater also provides a medium for transportation and energy production, governs settlement patterns, provides a major recreational resource for society, and inspires artistic and cultural expression.
The text below outlines the maps for this issue, then discusses some of the general relationships of water and the Earth.
Mapping freshwater in the Atlas of Canada
This Atlas issue will examine freshwater in Canada from a number of viewpoints. Specifically, it will examine four water themes in the following subtopics. These are listed below along with the names of the maps that are associated with each subtopic.
Distribution of Freshwater
- Current Water Levels
- Drainage Basins
- Drainage Patterns
- Glaciers and Icefields
- Groundwater
- Snowfall
- Wetlands
- Wetland Diversity
Uses of Water
- Agricultural Consumption / Irrigation
- Commercial and Institutional Water Consumption
- Domestic Water Consumption
- Industrial Water Consumption
- Hydroelectric and Freshwater
- Recreational Water Use
- Renewable Energy
Threats to Canada's Freshwater
- Coastal Sensitivity to Sea-level Rise
- Major Floods
- National Annual Precipitation 2050 Total Changes
- National Winter Precipitation 2050 Total Changes
- National Summer Precipitation 2050 Total Changes
- National Annual Temperature 2050 Total Changes
- National Winter Temperature 2050 Total Changes
- National Summer Temperature 2050 Total Changes
- Sensitivity of River Regions to Climate Change
- Sewage Treatment
- Threats to Ecosystem - Industrial Discharge Site
Water Quality
By using maps, users will become familiar with how freshwater in its many forms is distributed across Canada. Users will also have the opportunity to discover how freshwater relates geographically to human land use and Canada's ecosystems.
The data available to prepare these maps comes from a variety of sources. Two of the most important sources are two groups in Environment Canada: the National Water Issues Branch, and the Meteorological Service of Canada. The Atlas of Canada, itself, is another useful source because of past work done mapping water resources. Links to these and other sources are found in the other related resources section.
