Comparison of Trenchless vs. Open-Cut Construction Methods for the Replacement of a Leaking Water Distribution System

A water distribution system located in a growing residential community north of Dallas/Fort Worth, Texas, was experiencing a higher rate of water leakage and pipe breaks than was considered acceptable. The main breaks appeared to be a result of continued external corrosion. Experience has shown that the frequency of main breaks would likely increase, but the municipal officials were very concerned about the potential disruption that would occur with any replacement or rehabilitation project. A feasibility study demonstrated that a trenchless alternative could be successfully implemented at a lower cost than with conventional open-cut methods. Directional drilling was selected to replace approximately 3,962 m (13,000 ft) of water mains in multiple phases; the first phase included the construction of approximately 1,585 m (5,200 ft) during 2000. This paper describes the results of the technical and economic feasibility study, the detailed design performed, and the construction program implemented.