Case study: mapping the utilities of a 40-year-old facility

A large facility approached us needing a clear picture of its underground utility infrastructure. The site had been in continuous use for forty years and had been through repeated rounds of renovation. Services had been added, rerouted, capped and replaced over four decades, and no single record described what was actually in the ground.

That is the normal condition of an older complex. Each project documents its own work, nobody consolidates it, and the institutional memory leaves with the people who did the digging.

Consolidating the record

We began with the paperwork rather than the field. The existing as-builts were gathered, digitised and brought into our mapping software, which produced a single georeferenced base showing what the records claimed was there.

That base is not a survey. It is a set of hypotheses, and its value is that it tells the field crew where to look and which conflicts matter.

Surveying the complex

We then carried out a complete locate survey across the site, verifying the record against what was detectable in the ground. Lines that matched the drawings were confirmed. Lines that had moved were corrected. Services that appeared on no drawing at all were found and added.

Findings were captured with RTK, which records each located point as survey-grade coordinates rather than paint that lasts until the next rain.

The deliverable

The client received a .kmz report of the mapped infrastructure, which they can open, edit and extend themselves as the site changes.

• A single consolidated map of the utility infrastructure across the complex.

• Located lines captured as survey-grade points, not surface marks.

• Conflicts between the historical as-builts and the field findings identified.

• A file format the client controls, so the record stays current instead of expiring with the job.

Why a facility reaches this point

Forty years of renovation produces a drawer of drawings that each describe one project and no drawing that describes the site. Every subsequent excavation then carries the risk of the previous one, and each dig relies on whoever happens to remember the last.

Consolidating the record turns that into an asset the facility owns. The next project starts from a map rather than from a search, and the map improves with each job instead of starting over.

Related reading: utility mapping for property and construction projects.

Mapping for facilities and campuses

Advanced Underground Utility Locating has been locating private utilities since 2002. We locate the lines 811 will not mark, verify the public marks that were made, and mark public lines that were missed. RTK data collection and consolidated utility mapping are available for facilities that need a record rather than a one-day locate.

Spokane, Coeur d'Alene and the Idaho panhandle: 509-710-2621. Seattle, Tacoma and Portland: 509-954-8623. Bend, Medford and northern California: 541-678-0629. Eugene and Roseburg: 541-780-4149. Coos Bay and the Oregon Coast: 541-315-6728.