San Diego Region ‘Not Immune’ to Calgary Pipeline Failure

As soon as the Water Authority’s Martin Coghill heard about a catastrophic pipeline failure in Calgary two weeks ago, he knew how distressing it could be.

“When they’re in a situation where they call us for help from over 1,600 miles away, that’s a bad, bad day,” Coghill said.

The Water Authority was quickly able to send the final pieces of the infrastructure puzzle to Calgary to speed the city’s repairs. But Coghill, the Water Authority’s asset management manager, knows that similar problems could quickly impact San Diego County.

“In our aqueduct system, there are 80 miles of pre-stressed concrete cylinder pipe,” Coghill said. “That’s the same type of pipe that suffered catastrophic failure in Calgary.”

See how the Water Authority helped keep the water flowing in Calgary.

Pipeline failure potential in San Diego

The Water Authority experienced the same kind of problem in 1979, when pre-stressed pipes failed in the region for the first time, impacting the county’s water supply.

In response to that failure, the Water Authority spent the past 42 years relining 48 miles of pre-stressed pipe – or 60% of that type of pipe in the system – through a process called steel relining. That ongoing investment has significantly decreased the risk to the region’s water supply.

The catastrophic break in Canada led many across North America to recognize the unique space that water infrastructure plays in their daily life. As Kerry Black, a civil engineering professor at the University of Calgary said in a CBC interview, “when it breaks, it’s the first thing you’ll complain about but it’s the last thing you want to pay for.”

Across the United States, the potential for pipeline failure is an ongoing weakness, according to the American Society of Civil Engineers. It gave the nation’s water utilities a C- grade in its most recent national infrastructure report card in 2021. “Unfortunately, the system is aging and underfunded. There is a water main break every two minutes and an estimated six billion gallons of treated water lost each day in the U.S., enough to fill over 9,000 swimming pools,” said ASCE.

Investing in critical infrastructure upgrades in San Diego County

Coghill knows that even with all the advancements and investments in inspection and monitoring technologies, there are still gaps in the Water Authority’s ability to see problems coming. “Despite these technologies, we only have tools to actively monitor about two-thirds of the things that can go wrong with pre-stressed pipe,” Coghill said. “We’re not immune from a failure.”

For the Water Authority, protecting against a break in San Diego County happens on two parallel tracks and involves investing in critical infrastructure upgrades and testing.

“There are two roads we go down,” Coghill said. “One is a proactive approach in which every two years we re-evaluate what sections of the pre-stressed pipe are the next priorities based on risk and consequence of failure. That is put into the recommendation for the upcoming budget cycle for rehabilitation using steel liners. The other one is a more reactive approach, which I call the ‘imminent failure watch.’”

Modern tools track down early warning signs

That’s where the Water Authority’s installation of acoustic fiber optic cable allows engineers to hear a localized problem starting in real time, allowing the Water Authority to shut things down to fix the problem, and ideally with enough time to prevent a break.

This parallel track methodology has served the organization well since 2006—the last time a major failure of a prestressed pipe occurred—and in 2022, in response to data recorded by the acoustic monitoring system, identified the need for an urgent repair in the Bonsall area.

Coghill summarized the risks for our region. “Provided that we maintain a commitment to steel relining our prestressed pipe, and we maximize the use of available technologies, we are doing everything we possibly can to manage this type of pipe.”