Locating underground utilities using ground penetrating radar (GPR) technology became widespread following it’s commercial development in the 1970’s. GPR instrumentation was perceived as easy to use and provided a real-time picture of the subsurface. It was embraced by some as a panacea for seeing. The community soon realized that GPR missed features completely when the target has a dielectric constant closely matched that of surrounding soils, and that GPR just didn’t work at all in many common types of soils because of factors such as soil moisture, dispersion, and clutter.. (Recent advancements in hardware and software have made GPR instruments more “user friendly”, however the basic physical laws governing the method have not changed and data set problems such as dispersion and scattering remain.) These inherent interferences make GPR interpretation subjective and an experienced operator the most important element for the successful application of GPR. Misinterpreted data leads to a false data set and results in improperly marked locations that threaten worker safety.
As a result, GPR is not a replacement for conventional locators and is best used in conjunction with these instruments when conducting a utility mark-out. Conventional locators such as multi-frequency digital line tracers, induction instruments, and electromagnetic instruments each have an important place in tracing, identifying, and marking underground utilities. Reliable mark-out is achieved when trained and experienced personnel use the appropriate mix of locating tools deployed to address site-specific conditions.
Delta Geophysics provides formally trained operators with a background in earth science or geophysics for utility mark-out projects. A typical operator from Delta conducts over 200 utility mark-outs per year and brings over five years experience to the field. Our personnel work with a spectrum of geophysical instruments that are used in a manner that achieves the best result possible. All of our personnel receive factory and extensive field training, are OSHA 40-hour certified, and have work as a team since the company was founded in 2008. Delta’s work product is periodically peer reviewed by our chief geophysicist and project deliverables can include GPS positioned data, electronic reports, site maps, and AutoCad overlays in addition to field mark-out using industry standard color paint and flagging.
Delta prides itself in client communications that provide ethical and friendly counsel for all size projects, and would be delighted to discuss you next utility mark out project.