Condition Assessment and Rehabilitation Options for Peters Pipeline: A Case Study of Large-Diameter Raw Water Main Rehabilitation Study

This paper presents a condition assessment and rehabilitation analysis of the Peters Pipeline, a 3.2-mi long, 78″ to 63″ cast-in-place concrete pipe (CIPCP) raw water main operated by Stockton East Water District (SEWD). The study employed closed-circuit television (CCTV) inspection for the bare concrete section and visual inspection with sounding for the HDPE-lined section. Defect analysis utilized NASSCO's Pipeline Assessment Certification Program (PACP) to grade defects, calculate pipe ratings, and determine collapse stages for each pipe segment. Significant defects were identified, including circumferential cracks and fractures in the non-lined section, and liner separation, bulging, and infiltration in the lined portion. The study evaluated various rehabilitation options, including cured-in-place pipe (CIPP), sliplining, point repairs, and full replacement, considering benefits, disadvantages, constructability, and cost. Three rehabilitation scenarios were proposed: full-length renewal/replacement, targeted renewal with point repairs, and spot repairs to defer future costs. The impact of rehabilitation on conveyance capacity was assessed using an updated hydraulic model. Results showed that diameter reductions of up to 4 in. from CIPP or sliplining would have a negligible impact on desired flow, while an 8-in. reduction could decrease flow by 0.8 MGD. This study provides insights for water utilities facing similar challenges with aging large-diameter pipelines.