Land Use Impacts on Freshwater Quality

For the 2007 to 2009 period, freshwater quality was significantly different by land use category. Good and excellent freshwater quality was found more often in remote areas. Areas with more than one human development pressure had more stations with a poor or marginal freshwater quality ranking.

Freshwater quality by land use category for the 2007 to 2009 period, Canada

Chart: Freshwater quality by land use category for the 2007 to 2009 period, Canada

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How this indicator was calculated

Note: Freshwater quality was assessed using the Canadian Council of Ministers of the Environment’s Water Quality Index. Data from 2006-2008 were used for 24 Quebec stations because 2009 data were not available.
Source: Water quality data were assembled by Environment Canada from existing federal, provincial, territorial and joint water quality monitoring programs. Population, mining and land cover statistics for each station’s drainage area were provided by Statistics Canada.

Land use, or how humans have developed and managed land around a river, affects freshwater quality. In remote areas, there is less human development and rivers are surrounded by native plants and trees. Freshwater quality in remote areas is mainly determined by local soil conditions and tends to be rated excellent or good. Marginal or poor water quality in these areas can be caused by pollution travelling long distances through the air, such as acid rain. Water in rivers in areas close to cities tends to have more than one development pressure as people tend to live close to the areas where food is grown. The effects of runoff from agricultural fields, city streets and discharge from mines or wastewater treatment plants are stressors that can result in poor or marginal freshwater quality.

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