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EMERGING ISSUES

Emerging Water Quality Issues in the Bow River Basin Al Sosiak, Alberta Environment

Water quality in the mainstream of the Bow River has greatly improved over the past decade. Progress includes:

Wastewater Treatment:

• The City of Calgary has installed full tertiary treatment, including UV disinfection at both the Bonnybrooke and Fish Creek wastewater treatment plants.
• Various industrial plants no longer discharge to the Bow River.
• As a result, levels of nutrients, biomass of aquatic plants and other indicators have greatly declined in the Bow River.

Contamination site Clean Up:

• The containment project at the Canada Creosote site has successfully reduced the movement of contaminants to the river.

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EMERGING CHALLENGES

Urban Stormwater

• Urban stormwater from Calgary continues to have an adverse impact on water quality in the Bow River. In 1991, it was estimated that stormwater was then contributing 850 metric tonnes of total nitrogen and 86,000 tonnes of suspended sediments per year.
• Bacteria levels (as indicated by Escherichia coli) in the Bow River in Calgary have exceeded contact recreation limits during major summer storm events.
• As Calgary grows, this loading will continue to increase unless measures are taken, such as improved management of storm water.
• To prevent deterioration in water quality due to increasing urban storm water, the City of Calgary will be licensed for the combined loading from storm sewers and wastewater plants by 2003.
• Calgary will have to install appropriate treatment to prevent an increase in this combined loading.

Research - Protecting Calgary's Water Supply

• A recent study has determined that water quality in the Elbow River immediately upstream from Glenmore Reservoir has deteriorated over the past decade.
• Small increases in dissolved phosphorus, fecal coliform bacteria and turbidity have occurred, and some guidelines for recreation and the protection of aquatic life have been exceeded.
• These deteriorating trends in water quality indicators have not caused a detectable impact such as an increase in algal biomass in Glenmore Reservoir. There are insufficient data to determine the cause of these deteriorating trends.
• Alberta Environment and the City of Calgary together conducted surveys on the Elbow River and its tributaries in 1999, designed to determine the loading sources.
• Ultimately results from such surveys can be used to plan measures to reduce this loading and protect the Elbow River as a water supply for Calgary.

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