Manitoba Water Stewardship advises testing has shown that 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 Gimli Beach on Aug. 7, but returned to within the guideline by Aug. 10. The counts at Gimli Beach were also above the guideline on Aug. 13 and results from re-sampling are expected sometime late tomorrow afternoon.
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.
Escherichia coli counts were also above the guideline at Falcon Beach on Aug. 10, but quickly fell to below the guideline by Aug. 13.
Algae blooms were reported at Big Whiteshell Lake and Lake Wahtopanah (Rivers Reservoir) on Aug. 11 and 12, respectively. The number of blue-green algae cells were above the recreational water quality guideline of 100,000 cells per ml at both beaches. Both beaches will be posted with an algae advisory and will remain posted for the rest of the season. Sample results for the concentration of an algae toxin, microcystin-LR, were below detection.
Algae advisory signs let bathers know that algae blooms have been observed at the beach and provide some additional advice regarding avoiding contact with the water when algae blooms are present.
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.
