‘Always a risk’: Lethbridge taking stock of water infrastructure in light of Calgary main break

LETHBRIDGE, ALTA. –

In light of the ongoing water main repair in Calgary, Lethbridge city council was provided an update on the city’s pipe infrastructure and discussed if there’s any potential for a similar catastrophic break.

“There is always a risk,” said Doug Kaupp, general manager of water and wastewater with the city.

“Calgary has more of that type of pipe and it’s older than ours, but we’re always looking to learn how to avoid major mishaps that Calgary has unfortunately had to experience this summer.”

Each day, nearly 70 million litres of water flow from the water treatment plant through transmission lines to six reservoirs across the city.

“From there, it goes into the distribution system, which is a smaller pipe,” Kaupp explained.

“When we have a break in the distribution system, there’s a lot looping and piping in streets, going through intersections and valves that allow us to isolate a small area where the customers are affected.”

Kaupp says those distribution lines connect from the six reservoirs to homes and businesses. He says with the power to turn on and off valves, only a small number of residents would be impacted.

“A block or two would be out of water instead of, as in the case in Calgary, one of their two water treatment plants is unable to deliver water,” he said.

In Calgary, nearly 200 kilometres of pipe is high-pressured concrete (HYP), in Lethbridge only seven kilometres use that type.

Kaupp says if a transmission line were to break, only the reservoir it’s connected to would be affected – allowing water to continue to flow from the other five.

The last transmission pipeline inspection was performed on a steel line along Sixth Avenue South over 10 years ago.

“High-pressure concrete that we have, we’ve never inspected it,” he said.

“We had plans to about five years ago and the risk that was imposed by the inspection was too high.”

He says access points and constantly running water are the biggest challenges for inspections.

While there is always a risk of a break, Kaupp says Lethbridge’s concrete pipes were built in 1985, compared to Calgary’s in the 1970s with the only documented failures in the 70s pipe.

He says the size difference also plays a factor.

Calgary’s main feeder line was nearly two metres wide, and Lethbridge’s transmission lines are between 400-900 millimetres.

As the city continues to grow, Kaupp says water demand will also rise with a few priority projects on his list, including adding more capacity to the reservoirs in Uplands and Garry Station.

“Some capital projects that already approved to twin some critical sections of the transmission lines in the river valley and that is scheduled in the next couple of years,” he said.