Regional Water Quantity in Canadian Rivers
In 2010, water quantity conditions in most drainage regions across Canada were normal. Lower-than-normal water quantity was observed at the majority of monitoring stations in the St. Lawrence drainage region. Higher-than-normal water quantity was observed at the majority of monitoring stations in the Assiniboine–Red, Lower Saskatchewan–Nelson Ottawa, and Missouri drainage regions. Most drainage regions have a mix of low, normal or high water quantity at their stations. For example, while normal water quantity was observed at the majority of monitoring stations in the Lower Mackenzie, there were a large number of monitoring stations where conditions were higher-than-normal.
Percentage of monitoring stations in each drainage region with low, normal or high quantity with inset map of water quantity status of the majority of stations in each drainage region, Canada, 2010
Note: The 2010 water quantity classification for a station is based on comparison of the most frequently observed condition for that year with typical water quantity at that station between 1978 and 2007. Normal water quantities are specific to each region, and do not refer to the same amount of water in each drainage region (e.g., the normal water quantity on the Prairies is different from normal water quantity in the Maritimes). The numbers on the map refer to the drainage region numbers on the graph. There were not enough data to describe the Northern Quebec (18), North Shore–Gaspé (22), Arctic Coast–Islands (8) and Keewatin–Southern Baffin (16) drainage regions. The water quantity for the Great Lakes drainage region is based on rivers draining into the Great Lakes and not on the Great Lakes themselves.
Source Water Survey of Canada, Environment Canada (2012) HYDAT Database. Retrieved on 4 July, 2012.
A drainage region is an area of land where all the water on it drains to the same river, lake, wetland or ocean. Stations within a drainage region may be connected by a common water source. Every dam, municipal drinking water and wastewater treatment plant, and industrial facility may affect the quantity of water at the next station downstream.
Canada’s five major river basins can be divided into 11 major drainage areas and 25 drainage regions. The drainage regions are large and generally named for the major river or lake systems in Canada. Natural changes in temperature, rainfall and snowfall each year affect the water quantity in a river for that year.
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