In 11 a.m., an Olympic swimming pool’s worth of trash poured out of the old Mission City sewer pipe before anyone noticed.
The spill began around 10 p.m. Thursday, May 19, according to Tracy Kyle, director of engineering and public works. By the time public works staff were able to shut off the flow on Friday, about 2.5 million liters had leaked.
A valve had been mistakenly left open by a contractor, Kyle said, and no one from city staff had checked. She described it as a “communication failure”.
“During construction activities, there are multiple parties on site and communication is key,” Kyle said. “Future action will be to ensure that when contractors are asked to do something, we verify that they have actually done it.”
Three weeks earlier, a 40-year-old valve, attached to the old 750 millimeter pipe, had been used to switch the sewage flow to the new 900 millimeter pipe.
An emergency return to the old line took place on May 19, after storm damage caused a power outage at the port’s pumping station, which is still out of service, according to the city.
While Mission uses a SCADA system to detect pressure drops in its pipes, electrical issues at Harbor Station caused “alarms everywhere,” Kyle said.
She added that the penstock project to twin the sewer line from Mission to Abbotsford is still under construction; the city has not yet resumed operations nor is it linked to the SCADA system.
The city broke news of the spill on May 21, saying the cleanup should be complete by the end of the day, with a new environmental assessment to follow. The area affected is approximately 1.3 acres, according to the city.
Contractors with hydrovac trucks were mobilized over the weekend to vacuum the pooled waste and transport it to the James Water Treatment Plant in Abbotsford.
The figure of 2.5 million liters is based on measurement of missing wastewater data at the Abbotsford plant.
Kyle said there was a significant amount of standing water at the construction site prior to the spill, making it difficult to determine how much waste was recovered by the hydrovac trucks, or how much may have seeped into floor.
But there was no direct spillage into the Fraser River, and the sand and clay surface where the waste accumulated is dense and difficult to soak through, Kyle said.
City manager Mike Younie said the grounds will be restored to their pre-spill condition.
He said staff are awaiting soil sample test results and a remediation plan over the next few weeks; a debriefing with the staff will take place in the week, where responsibility will be discussed.
There is no estimate of the cost of the cleanup yet, as staff are still awaiting bills related to the sanitation plan, Younie said.
“We just don’t know what (the number) is at this point,” Younie said, adding that the city has reserves in place to handle these types of emergencies.
Kenny Braich, the owner, said he had had very little communication with city officials since being notified of the spill via text message. The penstock runs through part of the 87-acre homestead, which is currently for sale.
“We’re stunned and extremely irritated and agitated about this,” Braich said. “We still don’t understand what’s going on here.”
The property is the largest in Mission’s planned waterfront development area. Braich said these types of events reflect badly on the development community.
The penstock infrastructure upgrade, which the city began pushing for in 2016, reached a milestone in February when the new one-kilometre pipe was finally placed after being dredged under the Fraser River.
Environmental assessmentMissionWastewater treatment