What Lies beneath Riverside Drive? Evansville Water Digs for Answers

Evansville Water and Sewer Utility has a 36-inch potable water PCCP transmission main that serves as one of the backbones of their water system. The Riverside Drive Transmission Main’s condition was largely unknown, and the utility made the decision to perform a comprehensive condition assessment of the main to identify its current condition, make needed repairs, and perform forensic evaluations of the replaced pipe sticks to better understand the triggers for its deteriorated condition. The goal was to understand what lies beneath Riverside Drive and to maintain the pipeline’s integrity. The approach to assessing the main began with identifying inspection technologies capable of providing the most information possible. Electromagnetic technology used to identify broken wire wraps in the main was paired with a leak detection platform. In preparing for the inspections, the utility worked to minimize impacts to critical services and because of the selected technologies, were able to perform the inspections while keeping the main in service. The results of the inspections indicated approximately 5% of the pipeline sticks showed signs of distress in the wire wraps. Working with the inspection company, three sticks were identified for replacement. Once excavated, an external verification of the damage was performed confirming the proper sticks had been identified. The approach will then be to excavate and replace the pipe sticks, saving the worst for a forensic evaluation. Evansville Water and Sewer Utility needed to know why their transmission main is showing signs of distress, in order to take steps to extend the expected remaining useful life.