Environmental Thematic Maps and Graphics:
Annual total water storage change, by ecoprovince, 2002 to 2016

The title of this map is “Annual total water storage change, by ecoprovince, 2002 to 2016.” This map provides a visual representation of the total water storage change trends in Canada by ecoprovince.

On the page, there is one large map of Canada, a legend to the upper right and a scale bar below. The map delineates ecoprovince boundaries with a thin black line and ecoprovinces are labeled with a code. Fine black dashed lines show provincial boundaries. Below the map, ecoprovince codes and their corresponding names are listed for reference.

The map shows change in total water storage trends categorized into different colours. Increases in total water storage are shown as teal and blue, while decreases are shown in shades of brown.

The unit of measurement is millimetres (mm) per year. The legend contains six categories: 5 to 20 (teal), 0 to less than 5 (light blue), -10 to less than 0 (cream), -30 to less than -10 (caramel), -105 to less than -30 (dark brown), and data suppressed (grey). Grey diagonal hatching is used to indicate ecoprovinces where trends are not significant at the 90% confidence interval or above.

The largest decreases in total water storage from 2002 to 2016 were in ecoprovinces located in the Arctic Cordillera and Northern Arctic, as well as the Boreal Cordillera in the Yukon and northern British Columbia. For example, in the Northern Arctic Cordillera, water storage has been decreasing at an average rate of 105 mm per year, followed by the Southern Arctic Cordillera (‑103 mm/year) and the Ellesmere Basin (-96 mm/year). Increases in total water storage occurred much of central and eastern Canada, including the Eastern Boreal Plains (+19 mm/year), Central Grassland (+12 mm/year) and Parkland Prairies (+11 mm/year) ecoprovinces and in the Appalachian–Acadian Highlands (+15 mm/year).

Notes: Total water storage change is an estimate of the change in water stored in the environment as groundwater, soil moisture, surface water, snow and ice. Caution must be used in interpreting total water storage change results because of the level of uncertainty in the models, the short length of the time series, and the coarse resolution of the data. Data were suppressed for smaller ecoprovinces using a threshold of approximately 90,000 km². Statistically significant linear trends are presented at the 90% confidence interval or above.

Sources:
Statistics Canada, Environment and Energy Statistics Division, 2021, special tabulation based on Wang, S., et al., 2014, “Assessment of water budget for sixteen large drainage basins in Canada,” Journal of Hydrology, Vol. 512, pp. 1-15, https://doi.org/10.1016/j.jhydrol.2014.02.058 (accessed December 11, 2020);
Wang, S. and J. Li, 2016, “Terrestrial water storage climatology for Canada from GRACE satellite observations in 2002-2014,” Canadian Journal of Remote Sensing, Vol. 42, no. 3, pp. 190-202, https://doi.org/10.1080/07038992.2016.1171132 (accessed December 17, 2020);
Li, J., S. Wang and F. Zhou, 2016, "Time series analysis of long-term terrestrial water storage over Canada from GRACE satellites using principal component analysis," Canadian Journal of Remote Sensing, Vol. 42, no. 3, pp. 161-170, https://doi.org/10.1080/07038992.2016.1166042 (accessed March 23, 2021).