Saunderson PRV Lower Townsite Supply Lines HDD

The Saunderson PRV project is a multi-year project to upgrade water supply for the Lower Townsite (LTS) neighbourhood in Fort McMurray, Alberta. The project includes the construction of a new PRV chamber, extension of the existing primary high pressure water supply line, and the installation of a new supply line from the existing LTS Reservoir in the Abasand Heights neighborhood to the new PRV chamber by horizontal directional drilling (HDD). The focus of this paper is on the design and installation of the 445 m long and 914 mm diameter HDPE DR9 directionally drilled supply line crossing of Highway 63 from the LTS to the Abasand Heights plateau, a topographic elevation difference of approximately 65 m between entry and exit. Project complexities resulting from the elevation difference between drill entry and exit included risk of flush-backs during reaming passes, overbreak pipe support for pullback, buoyancy control requirements during pullback, and annular space grouting post-installation.