Methods of Overhead Transmission Line Construction and Prevention of Disturbance to the Archaeological Record: An Example from the Pennsylvania Piedmont

Daniel G. Roberts

A multi-phased archaeological survey in southeastern Pennsylvania in association with PECO Energy’s (formerly Philadelphia Electric Company) design of new overhead transmission lines provided an opportunity to observe the relationships between various transmission line construction practices and associated disturbance to archaeological sites. In this paper, various types of overhead transmission line support structures constructed by PECO Energy and their generalized construction methods are presented, followed by a discussion of the potential disturbances to archaeological sites found in Pennsylvania’s Piedmont soils attributable to those structures and methods. Such disturbances are evaluated in terms of soil disturbance and archaeological data loss potentially resulting from the various construction methods. It is intended that this evaluation will be of some benefit to members of the electric utility industry involved in future efforts with regard to archaeological resources planning.

Keywords: Direct and secondary effects; artifact exposure, breakage, and displacement; lattice structure; tubular steel pole; clearing and selective thinning; access roads; coring and blasting; uprooting of stumps; counterpoise system; ballast rock