Water quantity in the Athabasca sub-basin has undergone moderate change. Observations by Indigenous communities and scientists suggest much of the sub-basin is subject to changes in ice quality and timing of ice break-up and freeze-up dates in many waterbodies (earlier break-up and later freeze-up). Water levels in lakes, rivers, and creeks are more variable, with lower levels than in the past and decreasing trends in Athabasca River flows, while flows in tributaries did not change. These changes may be linked to changes in climate in the past several decades, such as rising air temperatures, more precipitation events and decreased snow mass in the Athabasca headwaters. Although water use in the Athabasca River has stabilized since the year 2000, many Indigenous communities remain concerned for the impacts of water withdrawals on river navigability during low flow periods. These observed changes in water quantity have the potential to impact aquatic ecosystem health and the ability for Indigenous communities to practice a traditional way of life in the sub-basin.
The following table summarizes the availability of information for each Water Quantity indicator.
Indigenous Knowledge Information and Data
Indigenous Knowledge Availability 1
Science Information and Data
Science Data Availability2
Snow and Ice
Local observations and oral histories of changes in snow quality, ice thickness, presence and break up of ice jams
Limited observations from few locations.
Available modeling information / stats on snow quality, ice thickness, presence and break up of ice jams
Snow data and analyses available. Limited availability of ice data; Water Survey of Canada stations may have approximate annual ice-on/off dates; limited ice monitoring.
Water Flows and Levels
Local observations and oral histories of changing flow / water levels in rivers / lakes and aquifers over time
Many observations from several locations.
Seasonal statistics including changes in flow / water levels in rivers / lakes and aquifers over time
Long-term data sets available from some Water Survey of Canada stations; analyzed two stations on the Athabasca River and four stations in major tributaries.
Local observations and oral histories of temperature, precipitation normal and extremes over time
No information found.
Temperature, precipitation normals and extremes over time
Data available from weather stations the basin, analyses completed.
Not assigned to a Sign or Signal.
Number of water licenses, purpose, volume allocated, and volume actually used vs. water flow / level; Water demand from various sectors, including dams, agriculture, oil and gas, etc., trends in water use over time
Water Licenses available but not retrieved for this report. Reports available.
1 Qualifiers for the availability of local and Indigenous Knowledge observations in publicly available sources: Limited = 1-2 observations; Some = 3-4 observations; Many = 5 or more observations; Few = 1-3 locations; Several = 4 or more locations
2 Qualifiers for the availability of science data in publicly available sources: Low = Individual studies or locations; Many = Network of monitoring stations across the basin
Snow & Ice
Changes in ice quality, freeze-up and break-up of ice jams have been observed in the lower Athabasca sub-basin. Snow mass has decreased in the Athabasca headwaters and increased in the lower Athabasca since 1981. Snow quality is impaired near Lower Athabasca oil sands mines.
Change in Average March Snow Mass (as Snow Water Equivalent, in mm/decade) in the Athabasca sub-basin 1980 to 2015. Positive (yellow, orange, red) values indicate increases in snow mass, negative (dark green) values indicate declines in snow mass.
Water Flows & Levels
Declining water levels in many rivers and lakes, particularly a decreasing trend in Athabasca River flows, are observed in the Athabasca sub-basin. These changes have resulted in significant impacts to river access and navigability for Indigenous communities. There is limited scientific evidence of how these changes impact aquatic ecosystem health.
Observations by elders and river users of lower water levels correlate with scientific findings, as the results of flow trend analysis show decreasing flows in the Athabasca River below Fort McMurray (this study). Mean annual streamflow at this location has decreased by 0.5 % annually from 1957 to 2018, corresponding to a 3.1 m3/s annual decrease. Monthly decreasing trends ranging from 0.2 to 0.6% annual reduction were significant for the months of September to February in Athabasca River below Fort McMurray, and also in late summer further upstream, at Athabasca, AB. No significant trends in flows were found in any of the analyzed tributaries, e.g., Clearwater River, McLeod River, Pembina River or Wolf Creek nor in spring freshet flows at any stations over the period of hydrometric record (mid-1950s to 2018, this study).
Data labels are the Sen’s slope (annual change in mean monthly flow in m3/s) and annual percent change relative to long term mean monthly flow. Data from the Water Survey of Canada
In a study with the Lesser Slave Lake Cree, an increase in flooding around Lesser Slave Lake in recent decades was the main theme in observations shared about water quantity. Increased flooding was attributed by participating community members to the removal of trees by forestry and oil and gas activities and the increased risk of flash floods in clear cut areas. A 2004 report by Alberta Environment attributed flooding around Lesser Slave Lake to increased sediment transport in the East and West Prairie and South Heart Rivers, which led to sediment deposits in downstream deltas, raised the river bed and consequently increased flood hazard in this area. Channel erosion and sediment transport increased dramatically as a result of extensive channelization that began in the early 1950s and culminated in 1974. Forestry, agriculture and road construction in the Lesser Slave Lake watershed were also noted as potential contributing factors.
Warmer air temperatures, increased precipitation and less winter snowfall have been observed in the Athabasca sub-basin since the mid-20th century. Climate data shows the greatest changes have occurred in winter compared to other seasons. Moisture availability shows substantial variation since the early 1900s, with slight long-term decreasing trends.
The greatest temperature increase (4.1°C) occurred in the winter, with the smallest increase of 1.3°C in the fall. The fact that cold regions and the cold season warm fastest is explained by the “Arctic amplification”. It is driven, amongst others, by the retreat of seasonal snow and ice that exposes darker surfaces and land cover underneath, introducing an additional warming effect across the region.
Temperature trends in the Athabasca Sub-basin (1948 – 2016). From: Bonsal et al. 2020
Temperature Change (°C)
Note: Spring: Mar-Apr-May, Summer: Jun-Jul-Aug, Fall: Sep-Oct-Nov, Winter: Dec-Jan-Feb
Annual precipitation in the Athabasca sub-basin has modestly increased (6.9%) overall from 1948 to 2012 as spring and summer precipitation increases were largely outweighed by winter decreases. The greatest increase in precipitation occurred in the spring and summer, while winter precipitation decreased significantly. Variations in precipitation have been hypothesized to be related to the Pacific Decadal Oscillation, a large-scale climate cycle driven by Pacific Ocean temperatures. Analyses of temperature and precipitation together indicated that there were major variations in moisture availability expressed as SPEI (Standardized Precipitation Evaporation Index), throughout the past 100+ years. In general, all regions were associated with wetter/cooler conditions from 1900 to 1915 and 1950 to 1980. Drier, warmer periods occurred from the mid-1910s through approximately 1950 and from the late 1990s until the end of the record in this study, 2011, particularly over the middle reach. These recent negative SPEI values have contributed to decreasing trends in river flows in the Athabasca sub-basin as discussed above and possibly in other sub-basins as well.
Precipitation Change (%)
Water use has increased over the last century due to increased population, industrial, agricultural and mining development, but has almost stabilized since about 2000.
Water use in the Alberta portion of the Athabasca sub-basin has increased over time, with increasing demand from a growing population, agricultural activity, industrial development (particularly forestry), and water management. Similarly, a population increase of 8.9% was reported from 1995 to 2010 in the Saskatchewan portion of the Athabasca sub-basin, indicating a similar increase in municipal demand across the sub-basin, although the population proportion of the sub-basin is minor. Largest water use increases in most sectors were recorded during the 1970s and 1980s, except the oil sands sector, where the largest increases occurred in the 1990s but where economic climate has resulted in large recent variations in production. During the early 2000s, water use had mostly stabilized.
Less than five percent of the average annual flow in the Athabasca River is currently allocated for surface water use by the petroleum industry, municipalities, forestry, and others. Of the five percent, less than one percent of the Athabasca River flow is used as many users do not use their full allocation, and return water to the river. As of 2018, the allocation to oil sands mining operations for water from the Athabasca River was under two and a half percent of the river’s average annual flow, while actual water withdrawn by oil sands mines in 2017 was less than one percent of the average annual flow). This usage has not pushed the lower Athabasca streamflows below the allowable flow thresholds defined by the surface water quantity management framework developed for the Lower Athabasca River by the Government of Alberta.
Although the volume of industrial water withdrawals represents a small percentage of flows in the Athabasca River and science-based evidence of the impacts on river flows has not been documented, Indigenous communities in the lower and middle Athabasca have observed a significant reduction in water levels that affects their ability to practice their Aboriginal rights (as described in Water Flows and Levels section of the Water Quantity indicator).