New Water Quality Study Highlights Need for Ongoing Protection of Grafton Lake
Bowen Island Municipality has reviewed data from a recent water quality assessment of Grafton Lake, which revealed a range of contaminants in the water. The findings highlight the importance of protecting the watershed long term, and the need for immediate actions to improve drinking water quality.
The assessment was conducted by the Raincoast Conservation Foundation through their Healthy Waters program, which focuses on monitoring pollution in BC’s watersheds. Grafton Lake was sampled in October 2024 as part of a one-time or “snapshot” assessment.
Grafton Lake provides essential drinking water for Bowen Island residents and supports native fish species, including coho salmon and cutthroat trout. While the assessment results do not indicate any immediate health risks, they highlight important long-term considerations for watershed health across the island.
“The Raincoast study reinforces the importance of ongoing monitoring, source control, and community education to protect water quality.” Said Mayor Andrew Leonard. “While there are no immediate safety concerns for drinking water, the Municipality recognizes the need to reduce future risks and safeguard this vital resource.”
Key Findings from the Raincoast Report:
- Grafton Lake had 125 contaminants detected from a total of 587 tested.
- The Lake ranked 8th most contaminated out of 21 source water sites in BC.
- The Lake showed relatively high levels of several pollutants, including sucralose, pharmaceuticals, and household chemicals.
- Of the substances present, concentrations were within current federal and provincial safety guidelines for drinking water and environmental quality, where guidelines exist.
The presence of sucralose, pharmaceuticals, and other human-sourced contaminants in Grafton Lake suggests that the primary source of contamination is likely septic system overflow or leaching from properties within the watershed.
“These compounds are not easily broken down in our bodies and end up in human waste. Therefore, they are useful tracers of human waste and being widely used to assess wastewater impacts downstream of homes, communities, and businesses in Canada.” Said Peter Ross, Senior Scientist & Director, Water Pollution, Raincoast Conservation Foundation.
The Municipality is currently developing a management plan for the Grafton Lake Watershed, in line with Council’s strategic goal of Responsible Ecosystem Protection. The project intends to balance the Lake’s role as a drinking water source with recreational use, current residential and agricultural land use, future development, and the area’s ecological values.
The Watershed Management Plan will include an assessment of values and threats, set management goals and strategies to achieve them, and establish guidelines for monitoring and adaptive management. Regular monitoring for wastewater contamination will be undertaken as recommended in the plan, to ensure that management actions are effectively protecting the watershed.
In the meantime, residents are encouraged to stay informed and take proactive steps to protect the island’s drinking water through proper septic maintenance, environmental stewardship, and sustainable living practices. Recommended actions include preserving natural riparian buffers, safely disposing of unused medications at local pharmacies, and ensuring septic systems are regularly maintained.
Fur further information please contact:
Carla Skuce
Manager of Environment & Parks Planning
604-947-4255 ext. 244
cskuce@bimbc.ca