How Advanced GPR Solved a Plumbing Nightmare at Trinity Christian School

The Challenge: A Critical Failure with No Maps

When GoRapid Plumbing was called to Trinity Christian School in Sharpsburg, GA, they faced a significant challenge: a damaged sewer system with no as-built information. Initial theories about the utility locations proved to be wildly inaccurate. The project stalled. How could they repair a system they couldn't find?

The situation was complicated by several factors:

·          Complex Subsurface: Previous attempts by other companies revealed a massive quantity of underground pipe signatures, far more than surface features suggested.

·          Ineffective Traditional Methods: Standard "push-and-paint" GPR techniques were minimally effective due to the sheer density of signals. EM Locator devices suffered from "signal jump," making it impossible to follow a single line.

·          Operational Constraints: The school was fully operational. Excavating to expose the pipe network was not an option, as it would shut down the primary access route for school buses and be tremendously cost-prohibitive.

GoRapid needed a partner who could accurately map the underground network without disrupting the school's function. They turned to Bigman Geophysical for a high-tech solution.

The Solution: A Two-Pronged GPR Approach

Bigman Geophysical's Dr. Sean McConnel arrived on-site with a Proceq GS8000 ground-penetrating radar (GPR) system. The project was divided into two distinct areas with different objectives.

Figure 1: Two areas of investigation shown in radar data. Area A required immediate identification of a specific pipe, while Area B needed full digital modeling.

Area A: Pinpointing the Critical Intersection

The most urgent task was to find a key pipe intersection that needed a cleanout installed immediately to resolve a sewage line failure. With a heavily disturbed subsurface and no above-ground features to clamp onto, traditional locating was impossible.

Using the advanced GPR system's freepath mode with an integrated SRS GPS, the operator quickly mapped all subsurface features. By analyzing the intersections, it was determined that only one could functionally connect the affected lines. This single point was flagged on the surface for excavation.

Figures 2 & 3: Target A shown in a top-down and 3D view, where the target intersection was clearly identified despite a complex subsurface environment.

Area B: Comprehensive Utility Network Mapping

The second area, near an athletic field, was a convergence point for an unknown number of utilities. The density of pipes had thwarted previous GPR operators who tried to follow and map each target one by one.

Bigman Geophysical employed a more robust strategy. The operator spent less than two hours on-site performing a bi-directional scanning pattern in a tight grid. This data was then processed with computer software to model the entire subsurface volume in 3D with a high degree of certainty.

Figure 4: Area B shown rendered as a 3D volume, with numerous pipes drawn below the surface.

Results: Accuracy, Speed, and Actionable Data

The combination of advanced GPR technology and expert data analysis delivered exceptional results. Bigman Geophysical was on-site for only a half-day, with the remote processing team completing the analysis and report in one full day.

·          Pinpoint Accuracy: The flagged pipe intersection in Area A was "exactly on target," allowing GoRapid to proceed with the emergency repair immediately.

·          Comprehensive Deliverables: A full 3D model of the pipe network in Area B was provided, giving GoRapid a complete and accurate map for future maintenance and repairs.

·          Efficiency: The project was completed within the quoted timeframe and cost, saving the school from expensive and disruptive exploratory excavations.

Figure 5: The final, highly accurate results of the Area B mapping shown from above.

Key Takeaway for the Plumbing Industry

This case study demonstrates that for complex sites with dense, unmapped utilities, traditional locating methods are often insufficient. Partnering with geophysical experts who utilize advanced GPR systems and 3D modeling software is not a luxury—it's a necessity. This approach mitigates risk, saves time and money, and provides the accurate, actionable data needed to get the job done right the first time.

This blog post is based on a case study involving GoRapid Plumbing and Bigman Geophysical. All information and images are sourced from the provided project documentation.