City discovers four more wire breaks on Bearspaw feeder line since repair work was completed

The City of Calgary announced that it has discovered four more wire breaks in the Bearspaw water main since July 25. Three of the breaks were discovered on Thursday and one on Friday.

The city’s total number of detected cable breaks on the main line now stands at nine, up one from the previous total announced earlier in the week, before the city retracted three breaks after they were misidentified by acoustic detection sensors.

“While this is not a sign that a main break is imminent, we still want to do some further investigation before making any further changes to our system or water restrictions,” said Nancy Mackay, Director of Water Services for the City of Calgary.

“We will continue to investigate and monitor the situation closely throughout the weekend. We will provide you with further updates each day.”

Overall, the city said the repair work and the feeder main continued to function well despite the breaks, with pressure in the main being increased to 75 percent during the week.

On July 22, Michael Thompson, the City of Calgary’s general manager of infrastructure services, said the city was not so concerned about the number of breaks, but rather the concentration of breaks in one particular pipe segment.

“We expect to hear wire breaks along the length of the pipe. As you may recall, the per-tensioned wire wraps around the pipe approximately 350 times per 16-foot pipe segment, so individual wire breaks are not a concern. It is one of the higher concentrations of individual pipe segment breaks that concerns us,” he said.

The results of the City of Calgary’s inspection of the Bearspaw main were also received on July 26. The City of Calgary indicated that it would take several more days to complete the analysis.

That diving inspection device, Thompson said Monday, was used to inspect the entire 7-mile (11-kilometer) pipeline.

The City of Calgary reported that water demand in the city fell to 593 million litres on Friday, compared to a peak of 683 million litres on July 24, during the height of that week’s heat wave.