Horizontal Directional Drilling Utilizing 36-Inch Flexible Restrained Joint Ductile Iron Pipe — A Successful First Experience

In operation since 1953, Erie County Water Authority (ECWA) is located in western New York state. ECWA operates as a self-sustaining business enterprise and pays for all operating expenses out of revenues generated from the sale of safe, clean water to a population of nearly 550,000. The Engineering Department is vital to ECWA's ability to provide high quality water and efficient service to this ever-expanding customer base with the least amount of disruption to their customers. One of the many responsibilities of Engineering is to oversee the study, design, construction and evaluation of conventional and potential alternative means for capital improvements to their transmission and distribution systems. A veteran staff has chosen Trenchless Technology Methods as part of their forward thinking and innovative five year capital improvement program. Contract No. EA-06, Water System Improvements in the Town of Amherst, New York, was designed as a 36-in (914mm) water transmission main approximately 11,000-feet (3.3km) long. A particularly challenging crossing of Ellicott Creek and the Corps of Engineers flood control channel at I-990 is the primary focus of this paper. ECWA and their engineer, Erdman-Anthony, chose to use flexible restrained joint ductile iron pipe in a horizontal directional drill (HDD) installation. The 785-feet (239m) 36-in (914mm) HDD installation was ECWA's first experience with HDD of any size. The 36-in (914mm) pipe was installed using the assembled-line method in two separate stages of approximately 400-feet (121m) each. Both stages were pulled through the pre-reamed borepath in a total time of approximately 72 minutes. This paper will discuss the successful installation of 36-in (914mm) flexible restrained joint ductile iron pipe using HDD and the importance of project management and coordination between ECWA, consulting engineer, general contractor, HDD sub contractor, and the pipe supplier.