Human Activity and the Environment: Freshwater in Canada, 1971 to 2013
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Imagine the amount of water tumbling over Niagara Falls every minute.
Canada's average annual water yield—an estimate of the country's supply of renewable freshwater—is so large that there is enough water to approximate a one-minute flow over Niagara Falls for each and every Canadian.
According to a new study in Human Activity and the Environment, the annual water yield averaged 3,478 km3 from 1971 to 2013. This yield represents, on average, 104,000 m3 for every single Canadian.
This huge volume of freshwater varies from year to year, by season and across different regions of the country.
Click here to access the full publication.
The annual water yield in southern Canada has fluctuated over time, from a high of 1,544 km3 in 1974 to a low of 1,165 km3 in 1987. In 2012, the total volume of freshwater flows was 1,294 km3.
The highest flows generally occur in spring and early summer. The median monthly water yield for southern Canada from 1971 to 2013 peaked at 218 km3 in May, before dropping to 76 km3 in August. The lowest came in February with a median flow of 50 km3.
Yield lowest on the Prairies
The annual average water yield corresponds to a depth of 349 mm across the entire country. This yield ranges from 50 mm on average across the Missouri, Assiniboine–Red, South Saskatchewan and North Saskatchewan drainage regions in the Prairies to 1,500 mm in the Pacific Coastal drainage region of British Columbia.
Water yields in the Okanagan–Similkameen and the Assiniboine–Red drainage regions are the most heavily influenced by spring flows. In these areas, the median water yields for April, May and June accounted for about three-quarters of the annual flows over the 1971-to-2013 period for both the Okanagan–Similkameen and the Assiniboine–Red.
The monthly water yield is most variable in the Assiniboine–Red, Missouri, Okanagan–Similkameen and the South Saskatchewan drainage regions. Periods of high or low flows can create water management challenges.
Canadian households conserving more
In 2013, Canadians withdrew 37.9 km3 (or 37,892 million m3) of water for economic and household activities. Although some of this water was consumed—for example, lost to evaporation or included in products—the majority was returned back to the environment after use.
The main water user in 2013 was the electric power generation, transmission and distribution industry (68%), followed by manufacturing (10%), households (9%), agriculture (5%) and mining and oil and gas extraction (3%).
Total household water use was 3.2 km3 in 2013, down 16% compared with 3.9 km3 in 2005. On a per capita basis, water use has fallen from approximately 330 litres each day in 2005 to 250 litres each day in 2013, in part due to improvements in the water efficiency of toilets and appliances.
Tracking water use related to the production of goods and services through to the end-user shows that households were responsible for 53% of total water use in 2013, followed by the production of goods and services for export at 30%.
Power generation drives intake
Surface freshwater intake was highest (23.5 km3) in the Great Lakes drainage region—these withdrawals accounted for 70% of the Canada total in 2013 and were mostly due to water intake for thermal-electric power production. Surface freshwater intake totalled 2.0 km3 in the St. Lawrence, 1.9 km3 in the North Saskatchewan and 1.5 km3 in the South Saskatchewan drainage regions.
Challenges in balancing water demand to water supply tend to peak in late summer. The highest surface water intake to water yield ratios for August 2013 occurred in the Assiniboine–Red and in the Great Lakes drainage regions, followed by the South Saskatchewan and Okanagan–Similkameen. Higher intake to yield ratios point to a higher possibility for water shortages, conflicts between competing uses, and the potential for insufficient instream flows for ecosystem requirements.
Links to climate
Canada's freshwater supply is affected by ongoing changes in precipitation and temperature patterns associated with climate change. For example, average annual temperature increased 2.6°C in the Mackenzie and 1.9°C in the Northwestern Forest climate regions in northern Canada from 1948 to 2015, causing some permafrost thawing and thereby modifying the hydrology of these areas.
Note to readers
This edition of Human Activity and the Environment provides updated statistics on freshwater supply and demand. The report also includes highlights, maps, charts and tables for each of Canada's 25 drainage regions.
Water yield is an estimate of freshwater runoff into streams and rivers and provides information on Canada's renewable freshwater supply. These estimates are derived from data on the monthly volume of unregulated flows in Canada's rivers and streams. Note that this estimate of renewable freshwater can include some non-renewable water (for example, melt-water from receding glaciers).
These estimates provide measures of the stock of renewable freshwater in Canada, a useful denominator against which to analyse the flows of water to and from the economy such as intake and discharge by industry and households.
Because there are fewer stations in northern Canada, only the long-term average annual water yield is publishable for these regions—data quality was insufficient to derive the monthly water yield or the change over time. Users should be aware of data limitations in instances where finer resolution or more precise data may be required. For more information see "The water yield for Canada as a 30-year average (1971 to 2000): Concepts, methodology and initial results," (, no. 7). 16-001-M
Water use estimates exclude water used for hydro-electric power generation. Water use by final demand attributes water use related to the production of goods and services to the end-user of that product rather than to the producer.
Surface freshwater intake estimates cover thermal-electric power plants, manufacturing, mining, drinking water plants and irrigation. They exclude the oil and gas industry and withdrawals from groundwater and marine waters.
These data are part of the Environmental Accounting Program, which follows the United Nation's statistical standard System of Environmental–Economic Accounting.
Drainage regions are a variant of Statistics Canada's Standard Drainage Area Classification 2003. This classification groups 974 sub-sub-drainage areas representing all land and interior freshwater bodies into 25 drainage regions. These drainage regions can be further grouped according to their outflow into one of five ocean drainage areas: the Pacific Ocean, Arctic Ocean, Gulf of Mexico, Hudson Bay or Atlantic Ocean.
Southern Canada is a statistical area delineated by a boundary separating the northern from the southern portion of the country.
Chat with an expert
The public is also invited to chat with an expert about this release, on Friday, March 24, 2017, from 2:00 to 3:00 p.m., Eastern Time.
The study "Freshwater in Canada " is now available in Human Activity and the Environment, 2016 (16-201-X).
Spatial data files for the average runoff in Canada and drainage region boundaries can be downloaded from the article and are also accessible from the Geographic products page of our website. They can also be accessed as web services on the Government of Canada web site Open Maps. See: Average annual runoff in Canada and Drainage regions of Canada.
For analytical information or to enquire about the concepts, methods or data quality of this release, contact François Soulard (613-882-8603, firstname.lastname@example.org) or Jennie Wang (604-362-8125; email@example.com), Environment, Energy and Transportation Statistics Division.
For more information contact us (toll-free 1-800-263-1136; 514-283-8300; STATCAN.infostats-infostats.STATCAN@canada.ca) or Media Relations (613-951-4636; STATCAN.mediahotline-ligneinfomedias.STATCAN@canada.ca).
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