Identification of subsurface drain locations with ground-penetrating radar

Abstract

Ground-penetrating radar (GPR) is a geophysical tool designed for subsurface probing of materials with contrasting dielectric properties. The applicability of this technique to locate agricultural drain tiles or tubes under some soil types and moisture conditions found in New Brunswick and Nova Scotia was evaluated. A method using GPR graphical outputs from adjacent paired parallel traverses was developed to verify tile drain signatures. Over 50 drains, installed from 1 to 50 years ago, in soils developed in morainal till, glaciofluvial, and glaciomarine deposits were detected with the GPR system and confirmed by excavation. These included both clay and plastic drains. With experience, reliability was found to be close to 100%. The possibility of using the system for determining depth to the drain is also discussed briefly. -Authors