Case Studies > Central Iowa: Manufacturing Facility
UIT performed a reconnaissance survey using its multi-sensor time-domain electromagnetic (TDEM) system to locate a high-pressure gas line at a manufacturing facility in central Iowa. While the UIT multi-channel GPR unit is typically used in such applications, soil conditions in central Iowa are not favorable to GPR probing due to extremely high clay content (due to the conductive nature of the clay material present at the site, GPR penetration below the ground surface is limited to 2 ft, or less).
This UIT application was performed with the multi-sensor TDEM system being towed along survey passes tracked by the Data Acquisition Shell (DAS) software (as illustrated in the above figure). The survey covered approximately 0.55 acres and was completed in 20 minutes. The TDEM data was processed and compiled with positioning information from a RTK differential GPS sensor to generate the 2-D contour plot of the results (shown in the figure below). The process that produced the final contour plots took less than 15 minutes to complete.
As evidenced in the contour plot, a gas line trending to the north and east is readily detected. Three other utility lines located in the southern part of the survey area are also identified. Depth estimates for the gas line were computed using half-width TDEM response formulations and inversion algorithms within UIT’s proprietary Semi-automated Process And DEtect (SPADE) software.