Oil spills this week in Bowker Creek and the Gorge Waterway are under control, says Saanich’s director of engineering.
“They’re contained at least within the property that we followed them back to,” Harley Machielse said.
“We’ll continue to monitor the dams and booms that we have in place over the next few days.”
Diesel oil leaking from a residential tank is the confirmed cause in the Bowker Creek case and suspected in the Gorge spill. Machielse said some tanks in the municipality are decades old.
“How do we, in time, have those come out of the ground … and removed, and remove that risk? It’s a challenging issue, for sure,” Machielse said.
Residents are encouraged to watch for spills.
“That’s typically how we get notified,” Machielse said.
The Bowker Creek spill was reported to Saanich on Monday night by the Oak Bay Fire Department, which was relaying a message from the public.
An oil sheen was spotted on the creek near Mortimer Street, in the area of Cedar Hill Cross Road and Shelbourne Street.
Saanich staff noted a strong smell of diesel and set up booms, but it proved difficult to find the source. More than 50 manhole covers were lifted in an effort to find where it was coming from.
Machielse said the effort was especially labour-intensive because it involved a portion of the creek that includes culverts, which are part of a system linked to an extensive networks of pipes.
The source was found Tuesday more than three kilometres away, traced to an oil tank on Kisber Avenue, near the Saanich-Oak Bay border.
A control measure being used for both spills is a “siphon dam,” Machielse said.
“You’re allowing the water to still drain, but the dam is stopping the contaminants at the surface from passing by,” he said. “The water goes underneath the dam.”
The spill on the Gorge Waterway was reported Tuesday, with the source quickly found to be a contaminated stormwater outlet.
Manholes were again lifted and the oil was traced to a home on Walter Avenue, a few blocks from the Gorge, where an underground oil tank is believed to be leaking.
A warning sign has been installed in Gorge Park near Admirals Road to alert people to the spill.