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Freshwater Quality in Canadian Rivers

For the 2009 to 2011 period, freshwater quality was assessed on select rivers throughout Canada where freshwater quality is at risk of being impaired by human activity.Footnote [1] Freshwater quality in rivers was rated excellent or good at 46% of monitoring sites, fair at 35% of sites, marginal at 17% of sites and poor at 2% of sites. Overall, existing freshwater quality in the majority of Canadian rivers is sufficient to maintain healthy river ecosystems.

National freshwater quality indicator for the 2009 to 2011 period, Canada

National freshwater quality indicator for the 2009 to 2011 period, Canada

Long Description

The bar graph presents the status of freshwater quality for the period 2009 to 2011 at 172 river monitoring sites selected to be representative of 16 drainage regions in Canada where human activities are most intense. The bars show the number of sites where freshwater quality for the protection of aquatic life was rated excellent (10), good (69), fair (60), marginal (30) and poor (3).

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How this indicator was calculated

Note: Freshwater quality was assessed at 172 sites on rivers throughout 16 of Canada's drainage regions where human activity is most intensive using the Canadian Council of Ministers of the Environment's Water Quality Index.
Source: Data assembled by Environment Canada from federal, provincial, territorial and joint water quality monitoring programs.

Freshwater provides essential habitat for aquatic plants and animals, supports many commercial and industrial uses, and is at the heart of many recreational activities. Freshwater quality is important to ensure lake and river ecosystems will remain healthy. It varies naturally across Canada because of the country's diverse geology and climate. The different ways in which people have developed the land around rivers and lakes also influences water quality. Each freshwater quality monitoring site has its own unique geography and set of human pressures.

The freshwater quality indicator reflects the overall state of water quality and integrates multiple pressures. The indicator presents freshwater quality measured at monitoring sites selected to be representative of populated regions in Canada. At each site, physical properties of water, such as temperature, and levels of chemical substances, such as nutrients and metals, were measured and compared to freshwater quality guidelines for the protection of aquatic life. When a freshwater quality guideline is exceeded, the freshwater quality rating is lowered.Footnote [2]

Change in the national freshwater quality indicator through time

Between 2003-05 and 2009-11, there was an increase in the percentage of sites rated good or excellent and a decline in the percentage of sites rated poor or marginal. Overall, the scores have significantly improved for 13 sites and declined for 4 sites. There has been no statistically significant change detected in the freshwater quality indicator scores for the remaining 84 sites where data were available for 2003 to 2011.

National freshwater quality indicator change between 2003-05 and 2009-11, Canada

National freshwater quality indicator change between 2003-05 and 2009-11, Canada

Long Description

The bar graph shows the percentage of sites where freshwater quality for the protection of aquatic life was rated excellent, good, fair, marginal and poor between 2003-2005 and 2009-2011. The pie chart, provided as an inset to the bar graph, shows the number of sites where the freshwater quality indicator has significantly improved, where it has significantly deteriorated, and where no change was detected. Between 2003-2005 and 2009-2011, the freshwater quality indicator rankings have significantly improved at 13 sites and declined at four sites. No change was detected at 84 sites.

View data for this chart
How this indicator was calculated

Note: Change in the indicator between the 2003-05 and 2009-11 periods was assessed at 101 sites in 16 drainage regions across Canada where historical data are available. For each site, change in the indicator was assessed using a consistent set of water quality guidelines and parameters through time.
Source: Data assembled by Environment Canada from federal, provincial, territorial and joint water quality monitoring programs.

The freshwater quality indicator changes slowly through time. Factors affecting freshwater quality and how it changes include the amount of pollution released directly into water and the amount reaching water from land and air. Human activities, such as urban growth, agricultural activities and industrial development, impacts the quality of water by changing how it moves across the land.

Freshwater quality is also affected by natural changes in rain and snowfall that change the amount of water running off the land or leaching through the soil carrying pollutants to rivers, lakes and reservoirs. The decline in water quality can be slowed by reducing pollution, upgrading a wastewater treatment plant, adopting beneficial land management practices or planting trees and native vegetation along a river.

Related indicators

Other information


Theme II: Maintaining Water Quality and Availability of the Federal Sustainable Development Strategy.
This indicator is used to measure progress toward Goal 3: Water Quality and Water Quantity – Protect and enhance water so that it is clean, safe and secure for all Canadians and supports healthy ecosystems of the Federal Sustainable Development Strategy 2013-2016.

Footnotes

Footnote 1

Water quality is assessed using the Canadian Council of Ministers of the Environment’s Water Quality Index using water quality guidelines for the protection of aquatic life. For more details about how the indicator is calculated, please refer to the Data Sources and Methods document.

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Footnote 2

For example, for some areas, elevated levels of naturally-occurring substances, such as minerals found in rocks, nutrients, glacier deposits and soils, lower freshwater quality index ratings. For a discussion of existing limitations, please refer to the Data Sources and Methods document.

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