Participants in a B.C. Wildlife Federation fish habitat stewardship workshop witnessed a localized fish kill firsthand on Cougar Creek last weekend.
Environmental chemist Josh Baker was explaining the dangers that toxins pose to salmon- and trout-bearing streams when they observed at least two dozen dead salmon and trout in the creek below Westview Drive. The fish were apparently poisoned when toxic compounds entered the creek with untreated stormwater from the road surface.
“North Delta could benefit from a first flush system to reduce the concentration of toxins that enter the water,” said Pete Willows of the Cougar Creek Streamkeepers, which was hosting the workshop. “It is extremely important during long periods of no rain to direct the first flush of water from road surfaces into vegetated areas to keep the accumulated toxins out of the watercourses.”
“Participants from all over the lower mainland got to observe the fish kill firsthand,” he said. “Our community has an amazing salmon bearing stream right in the middle of our community. There are so many things that can be addressed, from education to development practices, that could improve our relationship with the natural environment.
Cougar Creek is a rearing area for chum and coho salmon, cutthroat trout, and other species.
As a permanent and natural solution, a wetland enhancement could be implemented to absorb stormwater overflow and purify it before it reaches the watercourse, said Baker.
“These events are mostly due to urban pollutants entering a stream from the first rain after a dry period,” said Neil Fletcher, B.C. Wildlife Federation director of conservation stewardship. “The low flow combined with a higher concentration of pollutants is a recipe for disaster.”
“We invite the City of Delta to engage with the BCWF and the Cougar Creek Streamkeepers to generate effective solutions to this entirely preventable scenario,” said Fletcher.
More investments, resources, and attention from all levels of government are critical to support healthy watersheds. Salmon are indicators of environmental health.
Salmon in our urban watersheds benefit from integrated stormwater management techniques, which consider how a drop of water moves from our communities to the ocean, Fletcher explains. Solutions can incorporate green infrastructure such as restored wetlands to filter pollutants, sediment retention ponds, rain gardens, and provision of side channel habitats. This should be in combination with both public education and more engineered solutions closer to the source to limit the amount of toxins released into our waterways.
B.C. Wildlife Federation’s Fish Habitat Stewardship Workshops are held throughout the province to give communities and volunteers the tools they need to assess, enhance, and monitor wetlands and streams for the benefit of fish and wildlife.
BCWF and Cougar Creek Streamkeepers will be back at this site later in the year to improve the riparian corridor, remove invasive plants and introduce native plants and shrubs to mitigate some of the effects of urban encroachment.
PHOTO CAPTION: Pete Willows holds dead cutthroat trout and coho salmon from a fish kill downstream from the Westview Drive water discharge culvert. Credit Deborah Jones.
UPDATE: Researchers from Vancouver Island University are conducting water sampling in an effort to determine the cause of this fish kill. We will share developments regarding this story.