Five days after a contractor damaged water and sewer lines that forced a community near Calgary to declare a state of emergency, repairs are underway.
On Oct. 21, the City of Cochrane revealed that an unnamed contractor, doing work to twin the town’s sewer line, “impacted” sewage and water lines while preparing to drill.
The two ruptures sent sewage and water into the Bow River, Cochrane and Calgary’s water source. The significant loss of water reduced the town’s water availability.
By Oct. 22, the sewage line break was contained via a temporary bypass, but the water line continued to flow.
But on Oct. 26, the water line rupture was isolated and the leak was being addressed.
According to Cochrane’s CAO Mike Derricott, the water and sewage brew that flowed into the Bow River was a “significant” amount.
This led to the town of about 35,000 residents declaring a state of emergency on Oct. 24.
“As a result of the water and wastewater incident on Saturday, Oct. 21 and the uncontrolled impacts to the town of Cochrane’s water reservoir supply, our water reservoirs are at critical levels,” said Shawn Polley, Cochrane’s fire chief said on Oct. 24. “These levels directly impact our ability to provide water to the community. If water consumption continues at the current levels, we anticipate that some communities may soon be without water.”
Residents had already been asked to conserve water because the leak disrupted the filling of Cochrane’s water reservoirs. Potable water was trucked into town from Calgary and Rocky View County.
“We do have a fairly complex water system in Cochrane, in part due to the topography when you have a valley and hills. Moving water up and down those requires a number of reservoirs,” Derricott said. “We currently have two reservoirs that we would consider to be at critical levels.”
But instead of shutting down water supplies, the town opted to request mandatory water conservation via limiting bathing and laundry. The Spray Lake Sawmill was closed because it’s a big water consumer.
“There is a very significant process that follows if you depressurize a potable water system,” Derricott said. “You have to disinfect and flush and test before you can declare that water usable again and that could take a number of days to complete that process. So that is one of the main efforts we’re making is to avoid the need to have to go through that process.”
Derricott added even treated water from various locations is dissimilar due to the chemicals used in the water.
“Jurisdictions can use different processes and so part of the process has been to ensure that it’s safe to add the city of Calgary’s potable drinking water to our system and we’ve determined now that that will be an acceptable measure,” he said.
Dealing with the damaged line itself was a notable challenge.
That’s because the location of the line made repairs complicated, Cochrane Mayor Jeff Genung said.
The line got filled with water and crews couldn’t get down to the water line, he said.
Having a trench that wasn’t flooded with water became the priority.
“We know where the location of the break is, but in an ideal situation, when you have a water break, you’re able to operate valves, isolate the break and with the limited exposure, make the repair. This being a significant line, this has not been something we’ve been able to do yet,” Derricott said.
Regarding how the two lines were damaged, Derricott said, “We’re not prepared to comment on that other than that there was active work in the area and a line was impacted.”