Billings Heights Uses HDD and Jack-and-Bore to Install New 24-inch and 12-inch Lines

摘要

The County Water District of Billings Heights maintains more than 120 miles of pipe in Billings Heights, a suburb of Billings, the largest city in the state of Montana. Spurred by the energy boom, growth has been substantial through the last decade in Billings and the surrounding area.To accommodate growth, the District decided to upgrade their existing water distribution system, previously at its maximum capacity, by adding new transmission lines and a reservoir. The new transmission line includes over one mile of 24-inch diameter pipe and nearly 1.5 miles of 12-inch diameter pipe. Once complete, the 24-inch pipeline will convey water from the new 4-million-gallon Ox Bow Reservoir and will allow the District to retire three existing booster pump stations that will then only be used in times of emergency. The presence of several obstacles along the alignment that needed to be crossed without being disturbed required installation by horizontal directional drilling (HDD) and jack-and-bore methods. Due to the sensitivity of the surface, some sections of the 12 and 24-inch transmission lines were required to be installed within a casing pipe.The initiation of the watermain upgrade efforts, the decision process and procedures used to determine suitable materials and accommodate the sensitivity of the project location, and the various trenchless methods selected to lessen costs and environmental impacts will be discussed thoroughly in this paper. The main focus will be on the installation of water transmission mains at the highway, wetland and irrigation canal crossings.