Underground Utility Locating Prior to Daylighting/Potholing – Portland, OR

GPRS, LLC. of the Pacific Northwest was called by a large excavating and shoring contractor to conduct a utility locating scan prior to daylighting/potholing various utilities with a vacuum excavation truck. The project site was a an old hospital complex in the Southern area of Portland, where utilities of all ages and sizes were running unpredictably through the complex. Plans for the location of these utilities were available, but were written anywhere from 1920-1950 and had been proven mostly unreliable. The utilities in question were proposed to be quite deep (4’-8’) and ranged from water mains to large brick sewer drains. Electromagnetic locating was used to place a tone onto exposed water valves in the area, which narrowed down the location of the water mains in the area. GPR was then used to pinpoint these utilities down to +/- ¼’ of accuracy. The vacuum truck was then able to expose each utility with exact precision, using as little time and manpower as possible, which greatly cut costs for the contractor rather than having to hunt around an excavate large areas. A few unexpected utilities (storm drain and communication line) were also located in the area that were not mentioned on the plans at all.

The photo above was taken of the water mains that were located crossing the proposed excavation area. The location of these utilities that was described on the original plans placed these utilities 5’-10’ away from their actual location, which would have created massive delays when potholing took place.

The photo above shows these water mains after having been exposed by daylighting/potholing methods. GPRS was extremely accurate on the location of the utility lines, which greatly reduced the guesswork that would have been required to expose these utilities. A few unknown utilities in the area were also exposed, and would have been hit had they not been located prior to excavation.

If you are in need of, or would like a free quote for any of our underground utility locating services (private or public), such as utility locating, underground storage tank locating, soil boring clearance, trench scanning, or EMI mapping in the Pacific Northwest, please contact:
Jesse Moorhouse at (206) 200-9293 or at jesse.moorhouse@gprsinc.com.