The first water quality testing for Salt Spring Island’s summer swimming spots is on the books, and so far, the news is good.
Island Health reported samples collected Tuesday, May 20 from multiple locations at island lakes showed little to no E. coli, the indicator bacteria health departments use to identify the presence of fecal contamination and determine potential risk associated with swimming.
The testing showed just five (or fewer) bacteria per 100 mL at Blackburn, St. Mary, Stowel and Weston lakes, with the highest number coming from tests at Cusheon Lake — which showed only 10 counts of the bacteria in its 100-mL sample. Freshwater lakes are generally deemed acceptable for swimmers when single sample results show less than 400 counts per 100 mL, or when five samples in a row show over 200. The last time that happened on Salt Spring was the summer of 2022, when Island Health temporarily advised against swimming in Stowel Lake as counts there reached 495.
For Salt Spring’s ocean swimming enthusiasts, Island Health tests only at two beaches, both at Ganges Harbour — at Churchill Beach, off the end of Churchill Road, and in the water off Centennial Park. Beach swimming warnings are issued when single sample results for enterococci — the indicator bacteria Island Health uses for salt water — exceed 70 bacteria per 100 mL; the first samples this year of both showed “LT5,” indicating fewer than five bacteria per 100 mL at the harbour’s edge.
Indicators of fecal material in waterways come from numerous sources, according to Health Canada, commonly from agricultural runoff and insufficiently treated wastewater effluent. The Ganges Harbour Wastewater Treatment Plant releases treated and disinfected water from the sewer into the harbour — but through a nearly five-kilometre outfall that discharges well past Second Sister Island, at a depth of some 16 metres below sea level.