Recently a large general contractor asked to employ our services at a military base in central California to conduct a geophysical evaluation to delineate subsurface utilities prior to sending out an RFP to contractors for the total renovation of the facility, which was originally built in the late 1800’s. The as-built utility plan will allow contractors to make accurate assessments of time and materials required for upgrading individual utilities, as well as minimizing the potential for encountering unexpected utilities during trenching or excavating. Historical records indicated that some of the abandoned lines were even made out of wood.

Traverses using the geophysical instrumentation were taken over the site on random profiles, which were oriented to optimally recognize buried structures. In some cases where risers were present, the line tracer was used to trace out the lines. Our interpretation of the collected data took place in real time as the survey progressed, and the findings of our evaluation were marked on the ground, mapped on a site field sketch (see below), and reported to the client on completion of the survey. Of particular value on this project was the granular nature of the soil which allowed for great GPR imaging (see below).

Site Field Sketch

Example GPR Records