Water quantity in Canadian rivers

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In 2013, 27% of 866 water quantity stations were classified as having higher-than-normal quantity, 6% had lower-than-normal quantity and 67% had normal quantity.

From 2001 to 2013, Canada's rivers typically had normal water quantity with an increasing tendency for higher-than-normal quantity starting in 2010. The percentage of stations with lower-than-normal quantity has declined since 2001.

Water quantity at monitoring stations, Canada, 2001 to 2013

Column chart
Long description

The proportional column chart shows the percentage of stations with low, normal and high water quantity, on an annual basis, from 2001 to 2013. Over this period, Canada's rivers typically had normal water quantity.

Data for this chart
Water quantity at monitoring stations, Canada, 2001 to 2013
Year Total number of stations High quantity
(percentage of stations)
Normal quantity
(percentage of stations)
Low quantity
(percentage of stations)
2001 1241 5 68 27
2002 1237 5 79 16
2003 1254 2 77 21
2004 1253 9 85 7
2005 1247 22 74 4
2006 1242 11 78 11
2007 1248 12 80 9
2008 1245 10 86 4
2009 1256 8 82 10
2010 1252 20 73 8
2011 1226 26 68 7
2012 1145 16 70 14
2013 866 27 67 6

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How this indicator was calculated

Note: The water quantity classification for a station is based on a comparison of the most frequently observed flow condition in a given year with typical water quantity at that station between 1981 and 2010. The normal period for the Northern Quebec drainage region was 1971-2000, instead of 1981-2010, because of a data gap in the drainage region. The 2013 data has fewer stations contributing to the results because of delays getting data into the HYDAT database. Normal water quantities are specific to each region and do not refer to the same amount of water in each drainage region (e.g., normal water quantity in the Prairies is different from normal water quantity in the Maritimes).
Source: Environment and Climate Change Canada (2015) Water Survey of Canada, HYDAT Database.

Canada is a water-rich country, with its rivers and lakes accounting for 7% of the world's renewable freshwater.Footnote [1] However, even with all this water, shortages are a serious problem for regions of Canada when natural water supplies do not meet human demand.

Water quantity in Canadian rivers is measured as water flow, or the volume of water moving over a point, over a fixed period of time. Water flows in rivers, lakes and reservoirs generally follow changes in temperature, rainfall and snowfall throughout the year. In general, the landscape is wettest right after snow melt in the early spring and gradually dries out through the late summer and early fall. In any given year, more precipitation increases the amount of water in rivers, lakes or reservoirs, whereas warmer temperatures and less rain or snowfall will result in less water.

Over longer time scales, water quantity is also affected by weather patterns and ocean surface temperatures. In any given year, ocean surface waters interact with weather patterns to influence the amount of rain or snow that falls, which can bring about years with too much, or too little, water. For example, extended summer droughts on the Prairies, which cause lower-than-normal water flows, tend to take place when the southern Pacific Ocean warms during El Niño Southern Oscillation events. In contrast, the Prairies experience more rain and snow, causing higher-than-normal flows, when the ocean cools during La Niña events.Footnote [2] Climate change may increase the strength and occurrence of the El Niño Southern Oscillations.


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