Manitoba Water Stewardship advises testing has shown levels of Escherichia coli (E. coli) were within recreational water quality guidelines at most beaches monitored this week by the department.
Escherichia coli counts were above the guideline at West Grand Beach on July 24, 27 and 28 but returned to within guideline limits by July 29. Victoria and East Grand beaches were above the guideline on July 27 but returned to within the guideline by July 29. Escherichia coli counts were also above the guideline at Gimli beach on July 24, 27, 28 and 29 but returned to within the guideline by July 30. Exceedance of the guideline of 200 E. coli/100 ml was likely caused by weather conditions that caused winds and waves to wash bacteria out of the sand and into the bathing water.
Re-sampling results indicate that all beaches are currently within recreational water quality guidelines for E. coli.
On Lake Winnipeg, weather and lake level information appear to be good predictors of E. coli levels. Bacteria counts tend to increase when strong northerly winds cause water levels to temporarily increase and large waves wash bacteria out of beach sand. When calmer weather returns, E. coli bacteria levels typically fall quickly to below guideline levels.
Algae blooms were reported at Killarney and Pelican lakes on July 24 and 27. The number of blue-green algae cells was above the recreational water quality guideline at Killarney Lake beach and at four Pelican Lake beaches: Pelican Lake south (near Pleasant Valley), Pelican Lake north (near Ninette), and Manhattan and Strathcona beaches. The number of blue-green algae cells was also above the recreational water quality guideline at Meditation Lake. The concentration of an algae toxin, microcystin-LR, was below the recreational water quality guideline at all beaches tested this week.
All beaches with densities of blue-green algal cells above the guideline have been posted with algae advisory signs.
Algae blooms often appear in Manitoba lakes at this time of the year and can last until mid September. The formation of algae blooms is difficult to predict however warm and calm weather coupled with relatively high nutrient loads create ideal conditions for their development. Swimmers are reminded to avoid swimming in water if severe algae blooms are visible.
Results for all beaches across Manitoba are posted as they become available on Manitoba Water Stewardship’s website.
Each summer, Manitoba Water Stewardship routinely monitors about 60 beaches in Manitoba.
