Excerpt from Mackenzie River Basin: State of the Aquatic Ecosystem Report 2003 by the Mackenzie River Basin Board (p. 57-84). Full report available at http://www.mrbb.ca/information/34/index.html
The Athabasca River and Lake Athabasca together drain an area of about 269,000 square km in Alberta, Saskatchewan, and a small portion of the Northwest Territories. The sub-basin contains several types of ecosystems from glaciers, alpine meadows, and mountain forests in the Rocky Mountains to boreal forests and muskeg in northeastern Alberta. More than 155,000 people live in the sub-basin; the largest community is Fort McMurray. About 15% of the population is Aboriginal. The sub-basin includes lands covered by Treaties 6, 8, and 10, and there are 15 First Nations with over fourty reserves; Métis people live in both Alberta and Saskatchewan.
The Athabasca sub-basin is rich in non-renewable and renewable resources which are used by various industries, that include conventional oil and gas, oil sands development, coal mining, forestry, agriculture, commercial fishing, and uranium mining.
First Nations living within the Athabasca sub-basin have raised concerns about localized increases in turbidity, algal growth, and pollution, which they attribute to effluents from mining operations and urban centres. These concerns were limited to the Athabasca River in the vicinity of Fort McMurray.
Water quality at two monitoring sites has been consistently rated as ‘good’ or ‘excellent,’ however, there is discrepancy between the Alberta Water Quality Index and Traditional Knowledge of Water Quality in the Athabasca River. Traditional knowledge of water quality needs to be updated to determine whether this discrepancy still exists.
Flows in the Athabasca River are not significantly regulated by any dams or other structures. They tend to reflect the prevailing climatic conditions and are particularly affected by precipitation and evaporation. Annual water flow has neither increased or decreased in a consistent fashion over the past four decades. Differences among decades reflect differences in climatic conditions, and climate change may alter flow in the future. Alberta’s Water for Life strategy recognizes the need to manager water resources within the capacity of individual watersheds, a development that should improve water conservation in the province.
Although the water level of Lake Athabasca changes from season to season and year to year, it has not shown an increasing or decreasing trend. Two weirs were built to offset the effects of the Bennett Dam on water levels in Lake Athabasca and the Peace-Athabasca Delta, which nearly restored peak summer water levels to what they would have been under natural conditions. The effects of stabilized lake levels on the Peace-Athabasca Delta ecosystem need to be evaluated.
Aboriginal inhabitants of the Athabasca sub-basin rely on the water for travel, recreation, and fishing. Some people are eating fewer fish than they used to because of concerns about the quality and health of this resource.
The oil and gas industry and the forestry industry are two of the largest users of water in the Athabasca sub-basin. The total amount of water allocated for these and other uses is a small portion (<3%) of the total flow in the Athabasca River, but a large amount is either not used or is returned to the river system.
Commercial fishing occurs in several lakes. The industry is managed to ensure a sustainable harvest. The Alberta government is working to reduce the number of commercial operations and the number of nets, and is assessing populations of key fish stocks. In Saskatchewan, management is geared toward ensuring the sustainability of fish stocks, while at the same time meeting the demands of all users, including commercial, subsistence, and sport fishers.
The harvest of semi-aquatic fur-bearers is a source of income for some residents. The most significant change during the last decrease was an increase in the number of muskrat harvested following the 1996 flood of the Peace-Athabasca Delta. Overall, trapping has declined markedly in the past few decades, because it is not as profitable now as it used to be. The present level of trapping is not a significant pressure on semi-aquatic furbearer populations.
Based on information collected prior to 1995, some First Nations people along the lower reaches of the Athabasca Rivers and near Lake Athabasca noticed changes in populations of muskrats, beaver, and some fish. A general deterioration in fish quality was noted. It was also observed that the populations of goldeye in Lake Athabasca declined due to overfishing. It was further noted that this population of fish has partially recovered since limits on the catch were instituted. Information on traditional knowledge of fish in Lake Athabasca needs to be updated to determine if fish populations are still considered to be low.
There are eight aquatic and riparian-dependent wildlife species considered to be at risk or that may be at risk in the Athabasca sub-basin. Some of these species are naturally rare and are not under imminent threat from human activities. Some others are migratory and pressures on their populations likely arise in part of their range outside of the Athabasca sub-basin. In comparison to other regions of Canada, the species at risk or that may be at risk in the Athabasca sub-basin is low. Legislation at the provincial and national levels will improve protection for these and other species.
Waterfowl populations in northern Alberta change dramatically from year to year. Populations of some species are currently larger than their long-term average while others are smaller. The decline in pintail and scaup numbers over the past two decades is of particular concern. The commitment to additional research and monitoring of waterfowl populations by government and non-government agencies will improve our understanding of factors that affect populations, knowledge that is essential to improve conservation programs.
Aboriginal residents of Fort McMurray and Fort Chipewyan have changed their use of water because of health warnings and the risk of disease.
Because of high levels of mercury, dioxins and furans in some fish species, there are fish consumption advisories for several sites in the Athabasca sub-basin meant to protect people from excessive dietary exposure to environmental contaminants. While the mercury advisories are the result of naturally elevated levels of mercury in predatory fish in certain water bodies, the dioxin and furan advisories stem from industrial releases of these contaminants. Pulp mills have dramatically reduced their release of dioxins and furans into the Athabasca River. As a result, the fish advisory on the Athabasca has been eased in recent years. Government agencies need to monitor contaminant levels in fish and update advisories on a regular basis so that people will be able to make informed decisions about eating fish that they have caught themselves.