Fort Collins Utilities was faced with the need to rehabilitate two critical water supply pipelines. 
One was a 24-inch concrete transmission main that followed a very serpentine alignment along the Poudre Canyon north and west of Fort Collins. The concrete raw water line was built in the 1920s and is in excellent structural condition but has had a history of leaking joints due to pipe movement. The pipe is located in mountainous terrain, which makes access very difficult for repair. The other pipeline is a 27-inch steel finished water main. In contrast to the line in the Poudre Canyon, the steel line is a straight alignment and lies in the backyards of homes with very limited access. It has suffered from corrosion related leaks.
Stantec evaluated numerous rehabilitation or replacement solutions and selected Swagelining as the preferred rehabilitation methodology. The Poudre Canyon project lined 1,500 feet of concrete pipe. The steel pipeline project rehabilitated 2,600 feet of pipe and was lined in a one day pull. It was the longest 27-inch pull done in the United States for the liner subcontractor at the date of this writing.
Both projects were successfully completed and are now in service. The differences in the construction experiences between these two projects, however, were substantial. This paper will illustrate the lessons learned in the design and construction process through a compare and contrast analysis of the projects and outline the City’s plan to complete the rehabilitation of the 24-inch waterline.
The City of Fort Collins Utilities had identified two waterlines in need of rehabilitation or replacement. One pipeline carries raw water to the Water Treatment Facility (WTF) and follows a serpentine alignment along the Poudre Canyon (Poudre Canyon Waterline). The other pipeline carries finished water to the Foothills pressure zone in the northwest portion of the Utility’s service area and is the only feed to a water storage reservoir (Foothills Water Transmission Line). These are two critical waterlines representing two drastically different situations.
To read more about this project download the full paper written by Ken Matthews, P.E. Stantec Consulting, Fort Collins, Colorado and Owen Randall, P.E. City of Fort Collins, Fort Collins, Colorado.