Underground utility maps are often wrong – if they exist at all. Sometimes utility pipes or cables are relocated during repairs or renovations, but maps are not updated. Sometimes maps represent proposed plans that don’t show as-built locations. Sometimes, old maps are simply lost or disintegrated. People who fulfill their legal obligation to contact a central utility marking clearinghouse before digging or drilling may feel a false sense of security since lost or mis-mapped utilities generally will not be marked as a result of such a call. The result of digging or drilling in the presence of unknown, unmarked, unmapped, or incorrectly located utilities can be wasted excavation time (and money), expensive damage (more money), utility downtime (more money), and worst of all – personal injury or death.

Enviroscan uses state-of-the-art magnetic, electromagnetic (EM), sonic/acoustic, ground penetrating radar (GPR) and live line detector techniques to detect, trace, and map buried utilities or other obstructions in the vicinity of proposed boreholes or excavations.  The use of multiple techniques at every location ensures detection of metal, plastic, concrete, masonry, ceramic, and fiber optic pipes, cables, and structures.

Utilities are marked in the field using color-coded pavement paint and/or flagging.  The clearance zone diameter surrounding each borehole or excavation location can be specified by the client to allow for adjustment of the hole location based on drill rig or machinery access or other concerns.  Usually, field markings are all that is required.  However, Enviroscan is also capable of providing highly accurate surveying of markings using global positioning systems (GPS) or optical total stations. The survey data are used to make utility maps or overlays for geographic information systems (GIS).

Enviroscan has performed clearance for projects ranging from single holes on residential sites to hundreds of holes on industrial facilities and military installations – even on active airport runways.

Borehole and excavation utility clearance uses many of the same methods as utility mapping, but applies a different field procedure: clearance involves locating a spot (within a limited predefined area) where there are no underground obstructions, while utility mapping attempts to locate all utilities and structures throughout an entire site.  If your purpose is simply to dig or drill specific locations, utility clearance is far more economical than comprehensive utility mapping. As an example, a common application of utility clearance is the marking of precise underground storage tank (UST) footprints and associated piping to facilitate safe but close placement of monitoring wells or geoprobes.