Pipe Is Old, Street Is New, Valves Are Borrowed, and the PVC Is Blue

This paper will discuss the Yosemite Waterline Replacement Project’s planning and design, review important lessons learned from the construction phase, and will expand on the complexities of pipe bursting and waterline replacement in a heavily congested urban corridor with many technical constraints. Two major waterline breaks in Centennial, Colorado, prompted the Southgate Water District to assess the condition of an existing 18-in. waterline along Yosemite Street. The assessment determined that much of the line was buried at depths exceeding the pipe’s external load capacity. A parallel 16″/18″ waterline of similar characteristics was also found to be subject to the same risk factors. Hydraulic modeling determined that the two lines could be replaced with a single 20-in. diameter waterline. Several conditions made this project a good candidate for trenchless installations. However, dozens of intertie connections, heavy traffic, multiple pressure zones, and deep installation requirements presented challenges to a straightforward removal and replacement or pipe-bursting approach. A mixed approach was used, consisting of fusible PVC pipe bursting, dual parallel installations, and open-cut construction.