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Almost nine million Canadians depend on groundwater
In Canada, 8.9 million people, or 30.3% of the population, rely on groundwater for domestic use. ![Figure - Percentage of Canadian population reliant on groundwater (105kB)](/web/20061210104004im_/http://www2.ec.gc.ca/water/Gif/figure.gif)
Approximately two thirds of these users live in rural areas. In many areas, wells produce more reliable and less expensive water supplies than those obtained from nearby lakes, rivers and streams. The remaining users are located primarily in smaller municipalities where groundwater provides the primary source for their water supply systems. For instance, 100% of Prince Edward Island's population and over 60% of the population of New Brunswick rely on groundwater to meet their domestic needs.
Furthermore, the predominant use of groundwater varies by province. In Ontario, Prince Edward Island, New Brunswick, and the Yukon, the largest users of groundwater are municipalities; in Alberta, Saskatchewan, and Manitoba, the agricultural industry for livestock watering; in British Columbia, Quebec and the Northwest Territories, industry; and in Newfoundland and Nova Scotia, rural domestic use. Prince Edward Island is almost totally dependent on groundwater for all its uses.
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. ![Figure - Estimated depth and residence time of the world's water supply (46kB)](/web/20061210104004im_/http://www2.ec.gc.ca/water/Gif/figure.gif)
It is extremely difficult to estimate the volume of groundwater on the entire planet. For example, a recent review of the literature revealed estimated figures ranging from 7 000 000 to 330 000 000 cubic kilometres. However, all the estimates imply that if we do not include the water frozen in ice caps, glaciers and permanent snow, groundwater makes up almost the entire volume of the earth's usable fresh water. ![Figure - Groundwater and the world's freshwater supply (53kB)](/web/20061210104004im_/http://www2.ec.gc.ca/water/Gif/figure.gif)
Yet, this supply is often not easily accessible, and it may be difficult and expensive to develop these water supplies in some regions. The quality of the groundwater source is also a significant determining factor when identifying its use.
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