We provide Ground Penetrating Radar (GPR) services for locating numerous underground features, such as:

  • Utilities
  • Underground Storage Tanks
  • Septic Tanks
  • Voids
  • Manholes

All of these features, among others, are located using GPR and without drilling, probing, or digging.

How does GPR work?


GPR uses ultra-high frequency radio waves to determine the location and depth of buried objects. Using the GPR equipment, radio signals are transmitted into the ground until they reach an underground utility or other objects. When the radio waves hit a foreign material, they are reflected back to the GPR transmitter, where the results are displayed on a screen. The screen gives a visual of the reflection of the radio waves, and it appears on the screen as a peak or hyperbola. By analyzing the transmitted results, the technician can see where an interruption occurred, and interpret where the buried object is located. The signals are also saved for later review if further analysis is needed.

What does GPR do, and what does it measure?


GPR can map out all utilities, including metallic and non-metallic. Depending on the surface, GPR radio waves can reach utilities up to 100 feet deep in low conductivity materials such as dry sand or granite. Higher conductivity surfaces, such as clay or shale, will absorb the radio signals faster, only allowing them to reach 3 feet or less into the ground.

The frequency of the GPR antenna will also factor into how deep the radio signals can reach. A higher frequency GPR antenna will give higher resolution results for a shallower depth. An example would be a utility that is close to the surface, or rebar in concrete. Lower frequency antenna are used to locate deeper objects, but result in lower resolution results. This might be used to locate large objects buried deep underground, such as storage or septic tanks, or to investigate the geology of a site.

What are the limitations of GPR?


There are a few limitations to GPR that are important to be aware of. GPR radio waves cannot distinguish between different lines. For instance, a GPR reading cannot tell the difference between a gas line and a sewer line, it can just show the approximate depth and location. It also cannot tell the make up of a line. GPR is less effective on certain surfaces that are less conducive to radio signals, such as wet ground.

Why is GPR necessary?


GPR uses advanced technology to get one of the most accurate locates of underground features. It is used to collect Level B data on locating underground utilities. The only more accurate way of locating utilities would be to use excavation to remove the ground to physically expose the utilities. However, in certain situations, this can be expensive and impractical. GPR is the most efficient and accurate way to locate underground features and retrieve Level B data. Locating utilities before digging can save hundreds of thousands, and even millions of dollars. The consequences of hitting an unknown underground feature can be catastrophic. This is why GPR is important, Because What’s Underneath Matters.