Combined Directional Drilling to Reduce Design and Construction Costs

Early in the conceptual design stages of a water transmission main design project for the Wareham Fire District, Wareham, MA, it was learned that a second, independent municipal entity was planning to provide sewer service to the same area. In order to reduce design and construction costs, it was decided to have both the water and sewer lines designed by a single firm. This would eliminate or reduce costs involved by having two parties design similar crossings. Also, by including the construction of both lines in one bid package, mobilization and construction costs were reduced. The two installations consisted of 488 meters (1,600 linear feet) of 300 mm (12-inch) diameter High Density Polyethylene (HDPE) water main and a 488 meter (1,600 linear feet), 250 mm (10-inch) diameter HDPE casing sleeve in which a 150 mm (6-inch) force main was to be installed. Both lines were constructed under the Weweantic River, a tidal water body, by means of Horizontal Directional Drilling (HDD). The paper will present design, coordination and permitting issues for the project. It will cover the construction activities which included encountering boulders along the drill path. It will also present the drilling contractor's working closely with neighbors and residents who live adjacent to the work site.