Water pipe leak proving to be major headache
TOUGH FIX: Traffic chaos among concerns
There is a serious leak in a water main that runs through Stanley Park and supplies half of the City of Vancouver’s water.
For the past six weeks, chlorinated water has flowed from a hole in the pipe into Lost Lagoon and an attempt last weekend to plug the corroded pipe failed, said Sadhu Johnston, Vancouver’s city manager.
Metro Vancouver is heading the repair effort, but it could have big consequences for the city. If crews can’t figure out a different way to seal the pipe while water is flowing through it under pressure, the regional authority may need to restrict the flow of water to the downtown peninsula, Fairview, Mount Pleasant, Kitsilano and neighbourhoods west to the University of B.C., affecting residents, businesses and the capacity to fight fires, Johnston said in a recent email obtained by Postmedia.
Engineering consultants are trying to come up with a new repair strategy and it could be ready to go this week, Johnston told the mayor, city councillors and park board commissioners in the email.
The hole is nearly five metres below ground on the underside of Capilano Main No. 4, which was installed in the 1930s and carries treated water from the North Shore. It takes a seven-metre-deep hole just for workers to get at the issue, and that raises a structural problem because the leak is beside the busy Stanley Park causeway.
The Metro work team backfilled the excavation after its first attempt failed because of the risk associated with the proximity to the commuter route, Johnston wrote. The next time crews go in they will likely build a temporary retaining wall.
Approximately 430,000 litres of water are spilling from the hole in the main each day, said Greg Valou, a Metro Vancouver spokesman. At that level of daily flow over six weeks, enough water will have spilled to fill more than seven Olympic swimming pools. Repairing it will likely involve welding a steel plate onto the main in the area of the leak, he said.
In a worst-case scenario painted by Johnston, as many as two lanes of the causeway may need to be shut down and water pressure in the northern part of the city could drop significantly. Johnston called it a “very serious situation.”
Metro Vancouver is being more optimistic than the city. Normal water pressure can be maintained during the repair work, Valou said.
The water at the point of the leak carries about 0.7 mg of chlorine per litre. That is typical levels of water leaving Canadian treatment plants.
Until the hole is plugged, the leaking water will continue to reach Lost Lagoon, a freshwater sanctuary for herons, swans and ducks. But by the time it does, the chlorine will have been neutralized, Valou said.
“The water leaking from the water main is being de-chlorinated, tested and monitored to ensure no chlorinated water reaches Lost Lagoon,” Valou said.
If some chlorinated water did make it to the lagoon, it would not be unusual. In recent years, chlorinated water has been pumped into the lagoon to maintain water levels, Johnston said.
Metro Vancouver will not charge the city for the spilled water — a quantity valued at around $300 a day.