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Indicator Type: Environmental Condition
The River Bacterial Index describes river water quality based on the number of bacteria at selected sites on the province's six major river systems. The index evaluates bacterial densities in an annual series of water samples. These are collected monthly at 24 provincial Long-Term River Network sites (April through March). The River Bacterial Index is a component of the general River Water Quality Index. It rates water quality as "Excellent", "Good", "Fair," "Marginal" or "Poor", based on the presence of bacteria. Follow this link to learn more about the rating system.
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What does the indicator show?
The indicator for 2005-2006 suggests a somewhat higher incidence of bacterial contamination than the previous (2004-2005) reporting period, particularly in central and southern Alberta rivers. Northern rivers, including the Athabasca, Wapiti, Smoky, and Peace, demonstrated good to excellent Bacterial Index ratings, while many central and southern rivers, including the North Saskatchewan, Red Deer, Elbow, Bow, Oldman, and Milk Rivers, exhibited poor to fair ratings. In most instances, exceedances of water quality guidelines can be directly linked to unusually intense rainfall events during the summer of 2005. These events led to elevated surface runoff, which likely increased non-point source contribution of bacteria to rivers. Although some proportion of these bacteria may be related to human activities (e.g., confined livestock operations, urban runoff), other bacterial sources are known to occur naturally on the landscape.
Upgrades to municipal wastewater treatment processes in major urban centres, such as Calgary (1997), Red Deer (1999), and Edmonton (1998), have generally improved water quality downstream of these cities. Enhanced wastewater treatment tends to reduce bacteria and nutrients released into rivers. As a result, River Bacterial Index ratings downstream of all three cities have generally shown improvement since the late nineties (Click here for graphs), although the Pakan site on the North Saskatchewan has returned relatively low Index values in the last three reporting periods. At the present time, Alberta Environment is actively investigating the cause of high bacterial counts at Pakan.
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Why is this indicator important?
Rivers are an important source of water for agricultural use and are popular for recreational activities, such as swimming, boating, and fishing. Hence, bacterial contamination of these waterbodies may pose a risk to human, animal, and ecosystem health. The presence of fecal coliform bacteria or Escherichia coli in a water supply suggests that the water may have been recently contaminated with the fecal material of humans or other animals. This can be the result of improper or inadequate sewage treatment, overflow of municipal sewage systems, urban runoff, or other point and non-point sources of bacteria, such as livestock operations. Not only does this represent a potential health risk in itself, but it may also indicate concurrent contamination with other waterborne pollutants.
The River Bacterial Index is an environmental indicator that summarizes bacterial data into a composite descriptor. However, the index is not meant to replace the conventional scientific process of analyzing and interpreting technical data.
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What actions are being taken?
A number of natural and human factors can influence Index values. These include the volume of river flow, climatic conditions, the degree of development along rivers, non-point sources of runoff (such as agricultural fields), and point sources of effluent that discharge into rivers. Alberta's Water for Life strategy intends that all these factors will be considered in the protection of water quality and aquatic ecosystems, as part of the watershed approach. In keeping with this approach, continuous improvements to river water quality are being pursued through upgrades to municipal wastewater treatment facilities and infrastructure, through enhanced land use and watershed management practices, and via various other means.
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Links to additional information
More information on the River Bacterial Index can be found through the Alberta Environment Surface Water Quality website at: http://www3.gov.ab.ca/env/water/swq/
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Feedback
E-mail the SOE Coordinator: SOE.Coordinator@gov.ab.ca or complete this short on-line questionnaire to provide your feedback: http://www.zoomerang.com/
survey.zgi?p=WEB224DW6P3E2K.
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