City of Calgary’s Long-Time Feedermain Condition Assessment Program Shows This Is Not Their First Rodeo

The City of Calgary has long taken a proactive approach to the management of their large diameter feedermain network. This includes an advanced condition assessment strategy that combines an inspection program and risk analyses to develop a better understanding of the safety and reliability of the network. The program began in 2004, after the 1,200 mm (48-in.) McKnight Feedermain catastrophically failed and released 20 mL (5 mg) of water, flooding a roadway, and disrupting service to over 100,000 customers. An investigation determined that the failure occurred on a pipe section with coating that was eaten away in sulfate rich soils, allowing water to seep in and corrode the steel structure of the pipe. Over the years, successful inspections have allowed the City to proactively repair damaged pipes. This presentation will provide an update on Calgary's long-term strategy to pipeline management, including historical real-time structural monitoring results of the McKnight Feedermain and proactive leak detection success stories on their large diameter feedermain network. Inspection methods and technologies utilized, including damaged pipes that were identified and repaired prior to failure will be highlighted, along with challenges and recent improvements to the assessment process.