Water yield variability index, selected drainage region, 1971 to 2013
Map 2.2
Description for Map 2.2
The title of this map is "Water yield variability index, selected drainage regions, 1971 to 2013." On this map, the darker colours represent a higher the variability index. Category 1 (red) is 1.45 to 2.49, Category 2 (dark orange) is 0.93 to less than 1.45, Category 3 (burnt orange) is 0.63 to less than 0.93, Category 4 (cream) is 0.50 to less than 0.63 while Category 5 (white) represent regions where data are not available.
The Assiniboine–Red has the highest coefficient of variation for monthly flows, meaning the volume of water supplied in each month can vary widely from year to year. This was followed by the Missouri, Okanagan–Similkameen and the South Saskatchewan drainage regions. The Pacific Coastal drainage region had the lowest variability index indicating monthly water yield varies less from year to year.
Each drainage region boundary is outlined in black and labeled with a number to identify the area. A table is included which provides the full name of each drainage region, grouped by ocean drainage areas. The locations and names of some major cities in each province and territory are included on the map. Land areas outside of Canada are coloured light grey. Water is pale blue and major bodies, like oceans and bays, are named.
Notes: Variability is measured by using a coefficient of variation (CV) that allows the comparison of all months in all years of the 42-year time period. The CV of the water yield data is a measure of the dispersion or variation in the monthly yield values over the period 1971 to 2013 (and 1971 to 2012 for drainage region 1). It is defined as the ratio of the standard deviation of the monthly values to the mean. A higher CV indicates that the monthly data are more variable from year to year. The monthly variability was not calculated for drainage regions 5, 7, 8, 16, 17, 18, or the Labrador portion of 25.
Sources: Statistics Canada, Environment, Energy and Transportation Statistics Division, 2017, based on data from Environment and Climate Change Canada, 2015, Water Survey of Canada, Archived Hydrometric Data (HYDAT), (accessed December 3, 2015).
Category | Variability index | Colour |
---|---|---|
1 | 1.45 to 2.49 | Red |
2 | 0.93 to < 1.45 | Dark orange |
3 | 0.63 to < 0.93 | Burnt orange |
4 | 0.50 to < 0.63 | Cream |
5 | Data not available | White |
Ocean drainage areas and drainage regions | Code | Water yield variability index, 1971 to 2013Map 2.2 Note 1 |
---|---|---|
number | monthly CV | |
Pacific Ocean | ||
Pacific Coastal | 1 | 0.50 |
Fraser–Lower Mainland | 2 | 0.83 |
Okanagan–Similkameen | 3 | 1.44 |
Columbia | 4 | 1.04 |
Yukon | 5 | Note ..: not available for a specific reference period |
Arctic Ocean | ||
Peace–Athabasca | 6 | 1.01 |
Lower Mackenzie | 7 | Note ..: not available for a specific reference period |
Arctic Coast–Islands | 8 | Note ..: not available for a specific reference period |
Gulf of Mexico | ||
Missouri | 9 | 2.14 |
Hudson Bay | ||
North Saskatchewan | 10 | 1.04 |
South Saskatchewan | 11 | 1.10 |
Assiniboine–Red | 12 | 2.49 |
Winnipeg | 13 | 0.87 |
Lower Saskatchewan–Nelson | 14 | 0.92 |
Churchill | 15 | 0.75 |
Keewatin–Southern Baffin Island | 16 | Note ..: not available for a specific reference period |
Northern Ontario | 17 | Note ..: not available for a specific reference period |
Northern Quebec | 18 | Note ..: not available for a specific reference period |
Atlantic Ocean | ||
Great Lakes | 19 | 0.72 |
Ottawa | 20 | 0.80 |
St. Lawrence | 21 | 0.76 |
North Shore–Gaspé | 22 | 0.91 |
Saint John–St. Croix | 23 | 0.89 |
Maritime Coastal | 24 | 1.03 |
Newfoundland–Labrador | 25 | Note ..: not available for a specific reference period |
Newfoundland (Island)Note 2 | This cell is empty | 0.62 |
.. not available for a specific reference period
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