Trenchless technologies for drinking water pipeline installation and replacement

Much of the nation's drinking water lines are past their intended design lives and are in dire need of rehabilitation or replacement. The 1995 Infrastructure Report Card by the American Society of Civil Engineers scored the drinking water system in the United States a failing grade of D-. To compound this situation, increased urban growth has placed greater demand on existing systems, many of which do not have the capacity to meet this increased demand. With one eye on minimizing social impacts and another on tighter budgetary constraints, municipal engineers have begun to turn to trenchless technologies to address drinking water infrastructure issues. In particular, Horizontal Directional Drilling (HDD) and trenchless pipe replacement (or pipe bursting) are methods that are rapidly gaining acceptance as alternatives to traditional open-trenching for installing new and replacing deteriorated distribution systems. HDD is used for installing new water lines, while pipe bursting involves the replacement of deteriorated (or under capacity) lines with a new pipe of equal or larger diameter. This paper briefly describes each of these two trenchless methods and provides several case histories of their successful utilization in drinking water applications. Additionally, available and suitable pipe materials using trenchless methods are discussed.