Flooding and unusual weather patterns likely played a role in the unusually high amount of algae within Kalamalka Lake this year, states B.C.’s Regional District of North Okanagan (RDNO), which reports that it is switching out the current drinking water source to protect customers with Greater Vernon Water.
The water utility sources approximately 45% of its water from Kalamalka Lake water and its Mission Hill Water Treatment Plant, and 55% from the Duteau Creek water source and its treatment plant.
“Customers on the Kalamalka Lake source may have noticed a difference in the taste and smell of the water,” local officials stated in a public announcement. “Algae levels are not exceeding a level that poses a health risk, but the RDNO is switching water sources out of an abundance of caution,” officials added, noting that the shutoff began on October 25.
RDNO told residents that boiling water is not an effective or recommended action when algae is present, but customers could choose to use in-house filtration systems, such as Brita filters, while the sources were being switched over.
Customers not typically on the Duteau Creek source will “notice that the water is much softer and has a low alkalinity and pH,” local officials announced. This may be of interest to customers who have in-home water treatment systems or aquariums, officials added.
“Staff will continue to monitor water quality, notify customers of any further changes and when the Kalamalka Lake water source is turned back on,” RDNO said in its announcement.
Algae blooms in drinking water can cause gastroenteritis symptoms like vomiting, diarrhoea, fever and headaches.
Greater Vernon Water supplies the City of Vernon and some areas of the District of Coldstream and Spallumcheen. It also includes the Outback and Delcliffe, which are two small systems that draw water from Okanagan Lake.
Greater Vernon Water officials say that the algal blooms are part of the reason the utility is “actively seeking filtration” on the Kalamalka Lake source. Currently, different forms of filtration are being tested through its Mission Hill Water Treatment Plant Pilot Study run by Sandwell Engineering Services and four manufacturers.
At the Duteau Creek Water Treatment Plant, water is first treated with a coagulant and mixed to create a floc, according to city records. Clarification is achieved by dissolved air flotation. Chlorine is then added after treatment to ensure contact time for the removal of viruses, followed by UV disinfection. Mission Hill Water Treatment Plant uses a dual disinfection process of UV and chlorine.
The Mission Hill plant was commissioned September 30, 2006, and partially funded through the B.C. community water improvement program.