News from the American Sports Builders Association                                                        October  2017

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GPR Technology Gives a Deeper Look at Problems Below
Use Ground Penetrating Radar to Identify Below-Ground Issues Before You Dig In

by Steve Bush, CSFM, Agronmist and Owner of Bush Sports Turf

Scanning the field with Ground Penetrating Radar.

You wouldn’t want your doctor to initiate extensive surgery without first doing a thorough X-ray or MRI of the area to be operated on, right? He could be in the wrong area, overlook additional problems, and also do extensive damage in the process. The same problems can arise if you begin work on a sports field without first understanding what’s truly below its surface.

That is why Ground Penetrating Radar (GPR) technology is such a valuable tool for the sports builder to understand and take advantage of. Before you dig into a field, or project you can have an accurate map of what is below the surface. In a perfect world, irrigation systems drainage lines, root zones, utilities and other subsurface factors would all be exactly as mapped or intended. However, as we all know this is seldom the case. Either as built drawings are inaccurate, got lost, or do not exist at all.

What is GPR?

GPR is a quick, non-destructive, practical technology that accurately scopes out anomalies below the ground surface: foreign materials, depth variations, water drainage issues and more. It can detect objects made of any material. GPR works by sending a tiny pulse of energy into a material and recording the strength and the time required for the return of any reflected signal. GPR gathers data to create a thorough map of underground drains, pipes, water saturation, trenches and other objects in the layers below the surface. This data is then processed into a set of 3D images that allows you to accurately pinpoint certain locations and/or problem areas within the field. GPR gives you a complete view of what is below the surface without ever lifting a shovel.

GPR-Revealed Problems at Busch Stadium

When we initiated work on a complete field renovation at Busch Stadium, we started with GPR---and it’s a good thing we did. Our GPR scans revealed that the drainage system wasn’t built as designed and that areas had settled and were holding water. Also there were drain lines that had material in them as well as areas that had faulty connections. We were also able to map out the existing irrigation system as it had to be removed and replace as well.

With GPR we could see how thick the root zone and pea gravel were, which revealed another issue: although the root zone was supposed to be 12” deep across the entire field, GPR revealed variances of depth between 4” and 14” across the field. That information was vital in planning to calculate what materials and quantities would be needed to achieve an even and consistent root zone on the re build.

GPR and Ongoing Field Maintenance

Because of the elimination of guesswork is a valuable tool for planning. But it’s not a one-and-done thing. GPR can be used for troubleshooting and managing fields even long after renovations have been completed, making it an ideal for superintendents, facility operators, sports turf managers and everyone who depends on what is happening below the surface.

GPR can help continue to monitor compaction, moisture levels, drainage (or blockage), leaks, voids, deterioration and more. These diagnostic capabilities allow for precise, consistent assessment of whether or not conditions are improving, stabilized or deteriorating so that swift action can be taken where needed. In the short-run, GPR mapping allows accurate, real-time field analysis on demand. In the long-run, GPR saves extensive amounts of time and cost. It helps guarantee that things are as good below-ground as they are green above-ground.

Overview of underground drainage system showing main collectors and lateral lines.

© 2017 American Sports Builders Association 

9 Newport Drive, Suite 200 • Forest Hill, MD 21050 • 410-730-9595 •

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