GPR mapping to avoid utility conflicts prior to construction of the M-29 transmission line

Subsurface construction for utility installation and repair in urban environments presents many unique challenges. One of the most significant is the identification and location of existing underground utilities that may interfere with construction activities. The objective of this project was to establish that non-invasive subsurface imaging with multi-channel ground penetrating radar (GPR) is a viable method to map underground utilities, influence design and planning, and reduce the need for costly and disruptive test pits. ConEd via its consultants carried out a multi-channel GPR survey along approximately five miles of the planned route of the M-29 transmission line in Yonkers, NY as a demonstration of this capability. The GPR survey verified many of the existing utilities along the M-29 alignment as well as finding numerous unknown utilities that conflicted significantly with the planned construction, resulting in potential project cost savings that far exceed the cost of the GPR work itself.