Water

Photo of child fishing and kayaker

Overall, Canada may be considered a freshwater-rich country: on an average annual basis, Canadian rivers discharge close to 9% of the world's renewable water supply, while Canada has less than 1% of the world's population. Water is also highly visible in Canada: probably no country in the world has as much of its surface area covered by freshwater as does Canada. Of particular note are the Great Lakes. This set of lakes, which is shared with the United States, makes up the largest surface area of freshwater found in one place anywhere in the world. Water is used in the resources and energy industries.

List of Topics:

Distribution of Water

Watersheds

A watershed is an area that drains all precipitation received as a runoff or base flow (groundwater sources) into a particular river or set of rivers. The easiest way to describe the network of rivers and lakes on a small-scale map is to show the watersheds. In Canada, there is a detailed hierarchy of watersheds, ranging from the largest (drainage into oceans and their equivalents), down to the smallest ramification. Canada’s ocean watersheds are the Atlantic Ocean, Hudson Bay, Arctic Ocean, Pacific Ocean and Gulf of Mexico.

Hydrogeological Regions

Hydrogeological regions are areas in which the properties of sub-surface water, or groundwater, are broadly similar in geology, climate and topography. Hydrogeology is the branch of geology that deals with the distribution and movement of water beneath the earth’s surface. This map shows Canada’s nine hydrogeological regions, as well as a number of factors that affect groundwater properties.

Glaciers and Icefields

Glaciers and icefields are huge masses of ice, formed on land by the compaction and re-crystallization of snow, that move very slowly down slopes, or move outward due to their own weight. In Canada, an estimated area of 200 000 square kilometres, or about 2% of the country’s area is covered by glaciers and icefields. A huge quantity of freshwater is frozen in the polar ice caps and in high mountain glaciers. Glaciers and icefields are found in Western Cordillera and the mountains in the eastern Arctic. At present there are no reliable figures on the total number of glaciers in Canada. Glaciers exert a direct influence on the hydrologic cycle by slowing the passage of water through the cycle. Like groundwater, glaciers are excellent natural storehouses of water.

Wetlands

Wetlands are lands permanently or temporarily submerged or permeated by water, and characterized by plants adapted to saturated-soil conditions. Wetlands are the only ecosystem designated for conservation by international convention because they absorb the impact of hydrologic events, filter sediments and toxic substances, supply food and essential habitat for many species, provide products for food, energy, and building material, and are valuable recreational areas. Some wetlands help recharge groundwater, while others receive groundwater discharge. Wetlands are vulnerable to climatic variations and extreme events. Wetlands occur across most of Canada. Their location usually depends on local factors of drainage, topography, and surface material.

North America Watersheds (2006)

Drainage Patterns (1988)

Distribution of Wetlands (1986)

Wetland Regions (1986)

Water Quantity

Current Water Levels, 2007

The map shows 3172 hydrometric stations, 1491 active and 1681 inactive, located on rivers and lakes across the country. All the stations on the map are situated in a drainage area of 200 square kilometres or more. Hydrometric stations record information on the water level, flow velocity and discharge. Water level is the elevation at the water’s surface; flow velocity is the rate of water flow; and discharge is the amount of water flowing past a point in a unit of time.

Annual Mean Total Precipitation

The map shows the annual mean total precipitation. Over much of the continental interior of Canada, precipitation reaches its annual maximum in the summer months and falls as rain. October marks the transition from mainly rain to snowfall across northern Canada.

Average Maximum Snow Depth

This map shows the average maximum snow depth in centimetres computed over 18 winter seasons (1979 to 1997). Over southern Canada this usually occurs in January or February, while the time of maximum accumulation occurs much later in mountain areas and in the Arctic. The main features of the map are the pronounced maximum in snow accumulation over the western Cordillera, where snow depths can exceed several metres, with a secondary maximum over Quebec and Labrador. These maxima are related to their proximity to oceans, which act as sources of moisture and winter storms, and to the orographic effect of the mountains in the case of western Canada. The two maxima are linked by a band of higher snow accumulation that follows the boreal forest zone; this is a preferred track for winter storms. To the north of this zone is the relatively shallow snow cover of the Arctic (low snowfall with extensive wind packing). To the south, the depth of snow is limited by the shorter accumulation season and the substantial sublimation of snow over the Canadian Prairies.

Snowfall (Nunavut)

Nunavut lies in the Arctic, where cold temperatures mean that snow can fall at anytime in the year. Typically the ground is snow covered from September until June. Most of Nunavut has a dry Arctic climate receiving less than 200 centimetres of snow annually.

Streamflow (1993)

Seasonal Runoff (1974)

Runoff (1974)

Potential Evapotranspiration, Water Deficit, Growing Season (1974)

Climate Change

Global Annual Precipitation Scenario: 2050

A simulation of projected changes in mean annual precipitation from the period 1975 to 1995 to the period 2040 to 2060, is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Global Winter Precipitation Scenario: 2050

A simulation of projected changes in December to February precipitation from the period 1975 to 1995 to the period 2040 to 2060 is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Global Summer Precipitation Scenario: 2050

A simulation of projected changes in June-August precipitation from the period 1975 to 1995 to the period 2040 to 2060 is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Global Annual Precipitation Scenario: 2100

A simulation of projected changes in mean annual precipitation from the period 1975 to 1995 to the period 2080 to 2100 is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Global Winter Precipitation Scenario: 2100

A simulation of projected changes in December to February precipitation from the period 1975 to 1995 to the period 2080 to 2100 is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Global Summer Precipitation Scenario: 2100

A simulation of the projected changes in June to August precipitation from the period 1975 to 1995 to the period 2080 to 2100 is shown on this map. On average, precipitation increases, but it is not evenly distributed geographically. There are marked regions of decreasing, as well as increasing precipitation, over both land and ocean. Annual average precipitation generally increases over northern continents, and particularly during the winter. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

National Annual Precipitation Scenario: 2050

A simulation of projected changes in annual mean precipitation from the period 1961 to 1990 to the period 2040 to 2060 for Canada is shown on this map. In general, precipitation would increase as the century progresses and the climate warms and this is reflected in the annual average pattern. Also, the simulations show there are regions of both increasing and decreasing precipitation. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

National Winter Precipitation Scenario: 2050

A simulation of projected changes in winter (December to February) precipitation from the period 1961 to 1990 to the period 2040 to 2060 for Canada is shown on this map. In general, precipitation would increase as the century progresses and the climate warms. Projected precipitation changes are not evenly distributed geographically or seasonally. Precipitation is projected to decrease slightly for some higher latitude regions. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

National Summer Precipitation Scenario: 2050

A simulation of projected changes in summer (June to August) precipitation from the period 1961 to 1990 to the period 2040 to 2060 for Canada is shown on this map. Projected precipitation changes would not be evenly distributed geographically. Summer patterns show regions with both increases and decreases in precipitation. Warmer surface temperature would speed up the hydrological cycle at least partially, resulting in faster evaporation and more precipitation. The results are based on climate change simulations made with the Coupled Global Climate Model developed by Environment Canada.

Sensitivity of River Regions to Climate Change

The most sensitive river regions include the Atlantic coast, the Great Lakes-St. Lawrence Valley regions, the Rocky Mountains and the Prairies. The sensitivity projection for Canada's river regions in response to climate warming was derived based on an examination of the effects of projected precipitation changes on landscapes. Climate warming has the potential to cause substantial changes to flow in rivers. The most direct effects of projected climate change would be an increase in floods and river erosion.