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Severn Sound and Township of Tiny Beach Monitoring Program
Background
The Severn Sound Environmental Association Beach Monitoring Program is a partnership between the Simcoe Muskoka District Health
Unit (SMDHU), the Ontario Ministry of the Environment, the municipalities within the Severn Sound watershed, Parks Canada (Georgian Bay Islands National Park) and the SSEA. The purpose of the program is to provide regular monitoring microbiological water quality at selected swimming areas within the watershed. The results are used by the Health Unit to assess the risk that recreational use of the water may result in waterborne illness, and to provide warnings or advisories to the public. The sampling procedure follows the Ministry of Health Beach Management Protocol (1998).
Public swimming areas in Severn Sound were monitored by SSEA during
the summer months from the early 1990's to 2010. Areas in Georgian Bay Islands National Park are monitored by Parks Canada staff. Sampling
consists of a weekly collection of water samples at a minimum of five sites across each swimming area at a depth of 1 to
1.5 m. The samples are then analyzed for Escherichia coli (E. coli), an indicator bacteria selected by the Ministry of Health to assess the risk that swimming areas may harbor waterborne pathogens of fecal origin. Additional information collected during each sampling visit includes water temperature, pH, wind and wave conditions, precipitation, waterfowl numbers and bather numbers. These measurements help determine the importance of factors contributing to swimming area pollution. E. coli counts are averaged using a geometric mean, a type of mean that minimizes the effect of highly variable E. coli counts, and allows for better interpretation of data.
Why are beaches posted?
When the daily geometric mean of samples for a swimming area exceeds 100 E. coli per 100 ml, an advisory from the Health Unit is issued, and a sign stating, “UNSAFE FOR BATHING, HIGH LEVELS OF BACTERIA IN THESE WATERS MAY POSE A RISK TO YOUR HEALTH” is posted at the beach. The swimming area is also re-sampled by SSEA within a few days, to assess whether E. coli counts have decreased or remain elevated. Note that the assessment and decision to post the swimming area is based on samples that were collected prior to the posting date due to the time taken in analysis of samples. The advisory is removed only after satisfactory results of monitoring have been received by the Health Unit.
Postings
and Closures
How do bacteria enter a swimming area?
Sources of bacterial contamination can include:
• Stormwater washing fecal matter off streets, lawns and parks into nearby waters during rain events
• Poorly maintained or failing septic systems which can leak into waters near swimming areas
• Overflows from combined sewers that carry both sewage and stormwater in urban areas can discharge to waters near swimming areas during and after storm events
• Agricultural activities involving manure storage and handling can contribute to elevated bacteria when runoff enters waters near swimming areas
• Large numbers of waterfowl using a limited section of shoreline
How can you help?
• Observe stoop and scoop bylaws and dispose of pet waste properly
• Perform regular maintenance on septic systems and keep them in good working order
• Naturalize shorelines with native plants instead of mowed lawns to discourage large numbers of waterfowl from using swimming areas
• In rural areas, follow agricultural best management practices to control sources of bacteria from livestock
• In urban areas, minimize runoff from your property. For example, directing eaves trough downspouts onto the ground encourages infiltration rather than runoff to storm sewers
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