Summary of Assessment
Moderate to significant changes were observed in the Athabasca sub-basin in most aquatic ecosystem indicators. These changes are likely due to a combination of climate change and land uses. The land use footprint consists of mostly agriculture in the middle reach, oil and gas development in the lower Athabasca and forestry the entire watershed, except in the protected areas of the headwaters.
Water Quantity
- Reduced snow cover and warmer winter temperatures.
- Reduced flows in Athabasca River, more sandbars and difficult navigation, and concerns about water withdrawals for industrial use.
- Reduced water levels in the lower Athabasca River and Peace Athabasca Delta.
- Snow contamination near oil sands upgrading facilities in the Lower Athabasca Region.
Habitat & Species
- Significant reductions in fish populations, such as bull trout and Athabasca rainbow trout.
- Significant reductions in muskrat populations in the Peace-Athabasca Delta.
- Fish contamination in the middle and lower Athabasca River.
Water Quality
- Significant human footprint due to forestry in the entire sub-basin, agriculture in the Pembina watershed and surface bitumen mining footprints in the lower Athabasca.
- Cumulative point source impacts from pulp and paper mills have reduced dissolved oxygen and caused nutrient enrichment downstream of each source.
- Oil sands development has resulted in changes to water quality in the Lower Athabasca Region; however, these are more prominent in the tributaries than in the mainstem.
Health & Wellbeing
- Reduced access to traditional harvesting areas, particularly in the lower Athabasca River.
- Reduced fish consumption due to contamination and reduced muskrat consumption due to declining populations in the Peace-Athabasca Delta.
Water Quantity
- Reduced snow cover and warmer winter temperatures.
- Reduced flows in Athabasca River, more sandbars and difficult navigation, and concerns about water withdrawals for industrial use.
- Reduced water levels in the lower Athabasca River and Peace Athabasca Delta.
- Snow contamination near oil sands upgrading facilities in the Lower Athabasca Region.
Water Quality
- Significant human footprint due to forestry in the entire sub-basin, agriculture in the Pembina watershed and surface bitumen mining footprints in the lower Athabasca.
- Cumulative point source impacts from pulp and paper mills have reduced dissolved oxygen and caused nutrient enrichment downstream of each source.
- Oil sands development has resulted in changes to water quality in the Lower Athabasca Region; however, these are more prominent in the tributaries than in the mainstem.
Habitat & Species
- Significant reductions in fish populations, such as bull trout and Athabasca rainbow trout.
- Significant reductions in muskrat populations in the Peace-Athabasca Delta.
- Fish contamination in the middle and lower Athabasca River.
Health & Wellbeing
- Reduced access to traditional harvesting areas, particularly in the lower Athabasca River.
- Reduced fish consumption due to contamination and reduced muskrat consumption due to declining populations in the Peace-Athabasca Delta.
People & Places
The Athabasca sub-basin is the southernmost sub-basin in the Mackenzie River Basin with settlements primarily located along the Athabasca River. The sub-basin overlaps with the traditional territories of at least nine Indigenous groups. The lands of the Dane-zaa, Sekani (Tsay Keh Dene), Secwepemc (Shuswap), Salish, and Ktunaxa span the upper Athabasca, with major settlements located at Jasper and Hinton. The lands of the Nakota/Stony and Woodland Cree are located further east in the middle Athabasca, with settlements at Slave Lake, Town of Athabasca, and Swan Hills. The lower Athabasca, Lake Athabasca, and Peace-Athabasca Delta spans the territories of the Denesoline and the Métis and includes the communities of Fort McMurray, Fort McKay, Fort Chipewyan, Fond du Lac and Black Lake.
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 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 like in the sub-basin. 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.
Read more about Snow & Ice, Water Flows & Levels, Climate and Water Use
Changes in water quality have been reported by Indigenous communities and through scientific studies in some waterbodies in the Athabasca sub-basin. Indigenous communities have observed an increase in contaminants and sediment in lakes and rivers in the middle and lower Athabasca River and a change in the taste and colour of the water. These changes are thought to be associated with increased industrial activities, particularly oil sands mining and forestry, but studies also show localized influence of river channelization and straightening on water quality in the Lesser Slave watershed. Increases in blue-green algae blooms and nutrient enrichment in some lakes have been reported in studies by scientists, Indigenous communities, and local residents. Human footprint has increased over time and the downstream effects of industrial development remain a concern for local communities and there are significant concerns for how water contamination will continue to affect water quality and ecosystem health.
Read more about Water Quality, Benthic Invertebrates, Land Use and Effluent Discharges
Aquatic habitat and species in the Athabasca sub-basin are undergoing moderate change. This assessment is based on observations of changes in the abundance and health condition of some fish and furbearer species as reported by Indigenous communities. Less healthy fish with deformities and tumours and mass fish die-offs in some lakes have been observed by Indigenous communities and local residents of the middle and lower Athabasca watersheds. Studies based on scientific and local knowledge observations have documented elevated mercury concentrations in fish in the lower Athabasca. In the Peace-Athabasca Delta, a significant decline in muskrat populations and mass die-off events have been documented by scientists, elders and trappers, linked to increased contamination and changes in hydrologic patterns in the Delta. Scientific or Indigenous Knowledge observations of changes in wetland cover or riparian forests in the sub-basin were not found.
Changes in aquatic ecosystem health in the Athabasca sub-basin are having moderate impacts on the health and wellbeing of Indigenous communities. Health and wellbeing are closely linked to access to country foods. Many Indigenous communities report consuming less fish than in the past in response to concerns about contamination of the water and fish from upstream industrial projects and elevated mercury levels in some fish populations. Access to fishing and trapping areas is also disrupted by lower water levels and more navigable hazards, particularly the Athabasca River. A team of scientists, elders and trappers have documented a significant decline in muskrat populations from the Peace-Athabasca Delta in recent decades, and as a result, fewer Indigenous communities consume muskrat as part of their diet. Low availability of scientific data was found for levels of country food consumption in the Athabasca sub-basin.
