Regional Freshwater Quality in Canadian Rivers

For the 2010 to 2012 period, freshwater quality was assessed on select rivers throughout Canada where freshwater quality is at risk of being impaired by human activity.Footnote [1]

  • The highest proportion of sites rated good or excellent was found in the Columbia, Newfoundland–Labrador, Saint John–St. Croix and Ottawa River drainage regions
  • The highest proportion of sites with poor and marginal water quality was found in the St. Lawrence River, Great Lakes and Fraser–Lower Mainland drainage regions

Overall, freshwater quality in Canadian rivers can maintain healthy river ecosystems.

Freshwater quality in drainage regions for the 2010 to 2012 period, Canada


Long description

The stacked bar graph shows the number of sites where freshwater quality is rated excellent, good, fair, marginal and poor for the period 2010 to 2012. The map accompanying the graph displays the geographic area covered by each drainage region. The Columbia, Newfoundland–Labrador, and Saint John–St. Croix drainage regions had higher numbers of sites rated good or excellent. The St. Lawrence River and Great Lakes drainage regions had the highest number of sites with poor and marginal water quality.

Data for this chart
Freshwater quality in drainage regions for the 2010 to 2012 period, Canada
Drainage region name and IDPoor
(number of sites)
(number of sites)
(number of sites)
(number of sites)
(number of sites)
(number of sites)
Pacific Coastal (01)004206
Fraser–Lower Mainland (02)023117
Okanagan–Similkameen (03)001102
Columbia (04)002507
Peace–Athabasca (06)014016
North Saskatchewan (10)002406
South Saskatchewan (11)0225211
Assiniboine–Red (12)0393015
Winnipeg (13)000011
Lower Saskatchewan–Nelson (14)0147012
Great Lakes (19)0564116
Ottawa River (20)0126110
St. Lawrence (21)38125028
Saint John–St. Croix (23)0037010
Maritime Coastal (24)0278118
Newfoundland–Labrador (25)02311117

Download data file (Excel/CSV; 1.05 KB)

How this indicator was calculated

Note: Freshwater quality was assessed at 172 sites using the Canadian Council of Ministers of the Environment's Water Quality Index. The numbers on the map refer to the drainage region numbers on the graph.
Source: Data assembled by Environment Canada from federal, provincial, territorial and joint water quality monitoring programs.

A drainage region is an area of land where all the water on it drains into the same lake, river or ocean. Sites within a drainage region are connected by a common water source, a common geography, and the rivers that run among them. Canada has five major ocean drainage areas, which can be divided into 25 drainage regions. The drainage regions are large and are generally named for the major river or lake systems in Canada.

Freshwater quality at the headwaters of a river is generally better than at the mouth. Human activities, such as agriculture, industry and urban development, tend to accumulate as the water moves downstream. Pesticides, fertilizers, chemical pollutants and road salt from land-based activities, as well as treated municipal and industrial wastewater, enter the river all along its course building up at the mouth of the river.

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