Freshwater Quality in Canadian Rivers

For the 2008 to 2010 period, freshwater quality in rivers within populated regions of Canada was rated excellent or good at 44 percent of monitoring stations, fair at 39 percent of stations, marginal at 16 percent of stations, and poor at one percent of stations.

National freshwater quality indicator for the 2008 to 2010 period, Canada

National freshwater quality indicator for the 2008 to 2010 period, Canada

View data for this chart
How this indicator was calculated

Note: Freshwater quality was assessed at 172 stations throughout Canada’s 16 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 quality is important for the maintenance of healthy lake and river ecosystems. Freshwater provides essential habitat for aquatic plants and animals, supports many commercial and industrial uses, and is at the heart of many recreational activities. It varies widely across Canada because of the country’s diverse geography and the different ways in which people have developed the land around rivers and lakes. Each freshwater quality monitoring station is located in an area with its own unique geography and set of human pressures.

For the freshwater quality indicator, water quality was measured at monitoring stations selected to be representative of populated regions in Canada. At each station, physical properties of water (such as pH) and levels of chemical substances (such as nutrients and metals) were measured. To evaluate water quality, the measured physical properties and chemical substances were compared to water quality guidelines for the protection of aquatic life. When a water quality guideline is exceeded, the water quality rating is lowered.Footnote[1]

Change in the national freshwater quality indicator through time

Between 2003 and 2010, there was a decline in the percentage of stations rated poor or marginal, and an increase in the percentage of stations rated good or excellent. Overall, the scores have significantly improved for 12 stations and declined for 3 stations. There has been no statistically significant change detected in the freshwater quality indicator scores for the remaining 86 stations where data were available for 2003-2010.

National freshwater quality indicator change between 2003-05 and 2008-10, Canada

National freshwater quality indicator change between 2003-05 and 2008-10, Canada

View data for this chart
How this indicator was calculated

Note: Change in the indicator between the 2003-05 and 2008-10 periods was assessed at 101 stations in 16 drainage regions across Canada where historical data were available. For each station, 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 that reaches water from land and air. Human activities such as urban growth, agricultural activities and industrial development change how water moves across the land and can pollute water. Freshwater quality is also affected by natural changes in rain and snowfall that change the amount of water that runs off the land or leaches through the soil, carrying pollutants to rivers, lakes and reservoirs. The decline in water quality can be slowed by reducing pollution, planting trees along a river, upgrading a wastewater treatment plant, or adopting beneficial land management practices.

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

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. The Water Quality Index continues to be improved. For a discussion of existing limitations, please refer to the Data Sources and Methodsdocument.

Return to footnote1 referrer