There are 20 waterpower development facilities in the province, 11 of which are situated along the length of the Kananaskis/Bow river system. Each development requires a storage reservoir, a dam across the river, and a hydroelectric generation plant that actually converts waterpower to electricity. Approximately 5% of Alberta’s electricity needs are fulfilled by hydropower generation. This type of electricity generation is essentially a “clean” industry; it does not require many inputs and returns the same water back to the river on the lower side of the dam. However, these developments seriously affect aquatic ecosystems, especially fish such as the Bull Trout that need to migrate up-river to spawn. In order to minimize the impacts to natural ecosystems, environmental impact assessments are completed before the development of a new generating facility.
- How power is hydropower generated?
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- Hydropower developments generate approximately 5% of the Alberta’s energy.
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- A study on the Northern River Basins of Alberta concluded that dams and their associated reservoirs can negatively impact aquatic ecosystems.
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- Hydropower developments on Lake Minnewanka, the largest lake in Banff National Park, has resulted in large fluctuations of water levels such that typical aquatic and littoral habitats cannot establish themselves and significant amounts of sediment erode from the banks annually (Schindler, 2000).
More about how hydropower works:
The dam of a hydropower generating station functions to hold back water, so that it forms a reservoir behind it. This water can then be released at different rates, depending on the electrical needs of humans and the water needs of downstream ecosystems. As the water flows through a dam, it physically turns the large blades of a turbine, which is attached to a generator. As the blades turn, magnets present within the generator also turn, which generates alternating current (A/C current). This type of current is then converted to a higher-voltage current and carried away by power lines to places that need it, such as cities or industries.
Resource: A web page produced by the Environment Canada, Hydroelectric Power Generation.
More about Alberta’s hydropower developments:
Many of the province’s generating stations are owned by the TransAlta Corporation while others are owned by independent producers. The reservoirs associated with the power generation facilities maintain a steady flow of both electricity and water in times of shortage. Generally, the reservoirs are filled during spring and summer peak flows and they are gradually emptied through the colder months. Although hydroelectric power is a clean source of electricity, there are ecological consequences to their existence.
Resource: A web site produced by the Government of Alberta, Water for Life.
More about the impacts to aquatic ecosystems:
When a reservoir is created the riverbanks are widened. This floods terrestrial habitat that used to be along the banks of the river. Water storage reservoirs alter upstream and downstream river flows and can have a significant impact on aquatic life that depends on fast-flowing water. Reservoirs are also a source of methylmercury due to the build-up of organic material and associated microbes. The aquatic microbes feed on natural inorganic mercury and convert it to this harmful substance, which then contaminates aquatic life and ultimately enters higher food webs.
Resource: A report produced by the Government of Alberta, Northern River Basins Study Final Report.
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