Trust the Process: Great Lakes Water Authority’s Progressive Management Approach to Distressed Prestressed Concrete Cylinder Pipe

The Great Lakes Water Authority (GLWA) owns and operates the 14 Mile Road Transmission Main, which was constructed between 1967 and 1973 with 42-in. to 54-in. diameter prestressed concrete cylinder pipe (PCCP). This transmission main extends approximately 11 mi, with 8 mi having no redundancy. Since its construction, the pipeline has failed on two occasions: October 23, 2017, and October 31, 2021. In 2019, a free-swimming electromagnetic in-line inspection tool was used to characterize the number and location of broken wire wraps (BWWs) in the PCCP. The inline inspection identified high levels of distress in a concentrated area near the crossing of the GLWA transmission main and a set of high-pressure steel gas pipelines. Subsequent field testing strongly suggested that stray current from the impressed current cathodic protection (CP) system on the gas pipelines contributed to the observed BWWs in the GLWA transmission main. Based on the results of these tests, renewal of this portion of the GLWA main was recommended by HDR Michigan, Inc. (Prime Engineer). An alternatives analysis was performed to determine the most favorable approach for renewal. Renewal operations using carbon fiber reinforced polymer (CFRP) lining per (American Water Works Association) AWWA C305 were completed in 2023 and the transmission main was returned to service. During the course of the repair, significant planning and coordination took place with the GLWA member partners to implement alternative water operations to meet demands.