Navajo Gallup Water Supply Project Pipeline Design and Construction Evaluation

The Navajo Gallup water supply project reach 24.1/25 project will convey water from the San Juan River to four Navajo Nation (Nation) communities in northwest New Mexico. These Native American communities are among the most water-underserved in the United States. The project includes 13.7 miles of 14- and 10-inch pipeline and a pump station with a capacity of 1,500 gallons per minute. The Nation elected to use PVC for the transmission line, and also utilized fused PVC pipe (FPVCP) for the first time. FPVCP was used for joint restraint sections and for sections of the line where pipe joints were undesirable. This included arroyo crossings, locations of potential contamination, and areas of potential down-surge pressures. This paper will discuss the rationale, benefits, costs, and trade-offs of using FPVCP to provide thrust restraint, reduce risk of pipe failure due to soil erosion, and mitigate risk of contamination at pipe joints. Both advantages and disadvantages of FPVCP will be discussed, as well as lessons learned during construction and design aspects that may be improved upon in future designs using FPVCP as part of typical buried PVC pipe systems.