Addressing Geotechnical Challenges on Utah's Provo Reservoir Canal Enclosure Project

The Provo Reservoir Canal Enclosure Project (PRCEP) replaced a 160-year-old, 21-mile (34-kilometer) -long open canal with a 126-inch (3200-mm) -diameter steel pipeline to help address public safety concerns, reduce evaporation and seepage losses, improve water quality, increase capacity, and provide a reliable water delivery system to help meet the growing water needs of more than one million end users along the Wasatch Front of Utah. The canal alignment is primarily located on unconsolidated ancient lake sediment deposits, alluvial fans, stream deposits, and landslide deposits from the Wasatch Front Mountains. This paper presents a detailed discussion of the geotechnical challenges associated with these geologic materials. The geotechnical challenges of the project were further complicated by the need to design and prepare bid documents for several alternative materials for the enclosure, with the goal of identifying the most cost-effective method of construction and water conveyance for the project. These designs included precast concrete box culverts, cast-in-place concrete box culverts, non-cylinder reinforced concrete pressure pipe, and welded steel pressure pipe. With the challenges properly addressed, this monumental $150 million landmark project was completed one year ahead of schedule.