A warming climate in Canada will have impacts on water quantity and quality across the country. For example, in the Great Lakes Basin, climate models predict changes in annual streamflow and lake levels, with the possibility of more frequent flooding. In such cases, current sewage treatment facilities will be unable to cope with increased volumes of stormwater and sewage runoff.
In the Prairies, water levels in ponds, lakes and dugouts are forecasted to decline, leading to changes in water chemistry, which will mean less available drinking water in some rural regions.
Climate variability has a pronounced impact on the capacity of groundwater systems to maintain water supplies, in-stream conditions, and aquatic habitat; impacts such as these may increase as a result of climate change.
Canada has some of the largest freshwater reserves in the world. These reserves fluctuate widely due to natural variations in climate, and changes in climate caused by human activities could have dramatic and unpredictable effects. As the largest single North American source of freshwater for the Arctic Ocean, for example, the Mackenzie River plays an important part in regulating the thermohaline (temperature and salinity) circulation of the world’s oceans. A large-scale fluctuation in discharge from the Mackenzie would have consequences far beyond Canada’s borders.
Water S&T Research
In the Lake Winnipeg watershed, researchers are examining impacts of climate variability and change on the hydrologic and nutrient regimes. They are assessing hydrologic and nutrient transport processes in two representative sub-catchments of the Red and Assiniboine Basins by using the Soil and Water Assessment Tool (SWAT), which will be combined with global and regional climate model outputs to predict the impacts of future climate scenarios.
In the Great Lakes region, researchers are investigating the relation of groundwater to climate and determining the role of factors such as geology and topography. A particular emphasis is being placed on the discharge of groundwater to surface water and the influence that this has on aquatic habitat and species. Methodologies are being developed to detect the impacts of climate change on groundwater in the Great Lakes region and across Canada.
In western and northern Canada, researchers are examining past trends and variability in hydro-climatology and constructing future climatic scenarios of hydro-climatic conditions; they are also evaluating global climate models for their capacity to simulate current climate over various hydro-climatic regions within Canada.
In western Canada, researchers are examining the variability and causes of extreme hydro-climatic events such as droughts and assessing the potential future changes to these extremes using global and regional climate model projections.
A national assessment is underway to identify hydro-climatic regions where spring river ice break-up is the dominant control on annual flood events. Analysis of the frequency, duration and magnitude of these events will help researchers identify how climate is affecting this component of the hydrological cycle. This baseline information can be used, in conjunction with future climate scenarios, to highlight locations where significant environmental change is expected.
In the Mackenzie Delta region, scientists are analyzing peak spring water levels to determine climate-related variability in the spring break-up flood, which helps replenish delta ecosystems with water, sediment, and nutrients. They are also studying the role of ice jams in spring flooding and the hydro-climatic factors that control their occurrence. Scientists are working to improve models for climate change impact prediction; establishing surface energy balance over heterogeneous terrain; comparing with tower and aircraft estimates; and conducting analysis of heat and mass exchange of lakes.
Researchers are analyzing climatic trends in snow and ice in various regions of Canada to clarify the impact of climate change on snowpack conditions and implications to hydroelectric production; and assessing climatic factors controlling frequency and magnitude of extreme ice jam floods, which can have major socio-economic and ecological consequences.
A broad range of climate impacts on hydrology and aquatic systems is being assessed but a special focus has been placed on cold-regions' environments and cryospheric processes. Examples include: alpine snow resources, river ice and extreme hydrologic events, lake ice and aquatic responses, arctic river flow and freshwater budget of the Arctic Ocean, and the climatic redistribution of water resources. Research is conducted in western and northern Canada as well as around the circumpolar north.
In Canada’s polar region, researchers are investigating Great Bear Lake, Northwest Territories, to:
- quantify the mean and range of hydro-climatic and physical limnological variables;
- to apply thermal and hydrodynamic models to describe the lake heat exchange and temperature structure under current climatic conditions; and
- to assess the potential impact of climate change on the lake temperature using a range of climatic scenarios.