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.
