Fast Action to a Small Leak Avoids Possible Catastrophic Failure of a Large-Diameter Transmission Main

In January 2023, MWCo detected a leak on a 48-in. PCCP within a 4.38-mi long transmission main that conveys potable water from MWCo’s 60 MGD CJO WTP to their distribution system. The leak was detected within an existing easement adjacent to a major highway in the Township of Edison, NJ. In order to assess the cause and extent of this leak, MWCo shutdown the pipeline for an emergency repair and used this as an opportunity to perform a more detailed condition assessment of a portion of this transmission main. This opportunistic inspection consisted of a visual, sounding, and electromagnetic inspection of approximately 5,500 LF of the pipeline to evaluate distress and recommend pipes for repair. Based on these results and recommendations, MWCo elected to repair approximately 1,655 LF of the pipeline using CFRP. This paper presents the importance of the efficient application of specialty inspection, analysis, design of repairs, and implementation of these repairs. This proactive, comprehensive condition assessment and repair approach prevented possible catastrophic failure and should prevent future leaks and maintain the reliability of this transmission main for years to come.