Quamichan Lake aeration trials begin to restore water quality

Aeration trials are underway at Quamichan Lake to determine how to remediate nutrients and control the development of algae blooms. 

Senior environmental specialist Dr. Dave Preikshot delivered a presentation to the Quamichan Lake Neighbourhood Society in North Cowichan on Sunday to explain what the trial will do and how it will affect the lake. 

The three enclosures, now located on Quamichan Lake, are intended to provide insight into how to address increasing contamination of the lake. Preikshot said the enclosures will test a variety of methods as part of restoration efforts. 

“We’re working to develop different approaches and techniques in testing which involve aeration, and the addition of iron and aluminum,” he said. “We’ll be using the three enclosures over the summer to test different configurations and mixtures of those approaches to control nutrients and how cyanobacteria evolve in the lake. 

“Hopefully this will give us a plan as to how we can better manage nutrients in the lake, so this isn’t as much of a problem in the future.” 

The first samples of the lake have already been drawn, and Preikshot said the next step is to activate the aerators and gradually observe how the lake responds. 

“Once the test of the aerators — and their performance — is done, we’ll be looking at the performance in combination with iron and aluminum,” he said. 

The purpose of the trials is to control the amount of cyanobacteria in Quamichan Lake, a species Preikshot said can be toxic. 

“Some species can be associated with toxic byproducts. In 2017, cyanobacteria blooms led to the death of two dogs and this is what we’re trying to control,” he said. “The health effects on humans are less dire, but it’s not something we want folks exposed to.” 

The municipality hopes the trials will attract the attention of senior levels of government and spark interest in water quality management, which Preikshot said falls under federal and provincial regulation. 

Last year, the Municipality of North Cowichan received approval to proceed with the aeration trials after residents raised concerns about water quality in the lake. 

The aerators are eight-metre-diameter cylindrical enclosures that are anchored to the lakebed. 

Results are expected to be shared with council once the trials are complete. 

The project is funded through the Cowichan Valley Regional District’s Drinking Water and Watershed Protection Program.