GPR is Ground Penetrating Radar – essentially this is a machine that transmits electromagnetic waves into the ground and then measuring how these bounce back off whatever lies beneath the soil
The machines look like Flymo’s with four wheels and an Ipad on the handle – you simply walk them around over the ground you want to scan.
“Wow… I could combine with a round of golf, but what’s the point?” you ask.
Well its like X-ray for the ground and shows you what lies buried beneath.
Note this is different to metal detecting though – that just picks up metal.
GPR picks up everything from buried hand guns through to bodies and is generally used by the police/military but the role we use it for is finding old pipework as its old pipework that contains the rats.
Everybody else out there will use a drain camera to find old pipework as once the camera is in the pipe then a ‘sonde’ (please Google for description) will locate where the camera is above ground plus also tell you how deep it is.
Because the camera is in the pipe, once you find the camera then you find the pipe all being well.
And in most cases this works just fine but it is entirely dependent on getting the camera in the pipe – and this isn’t always possible.
Why? Because sometimes some waste systems are completely decommissioned over time rendering them buried and invisible from above ground because there is nothing remaining that connects onto them.
However they are still connected to a sewer and therefore will still pipe rats into a building if various aspects are broken/uncapped/built over etc.
If there is nothing connected to these hidden systems above ground, then there is nowhere to put a camera and ultimately there is no way to find the pipework!
This is then a huge problem as ultimately the only people that know where the pipe lies are the men that built the system – experience tells us that when the property is pre-1980 chances of finding these men on Facebook etc. to ask the question is slim.
So this is where GPR steps in – this doesn’t need a camera in a pipe as it blasts its electromagnetic waves through the ground which dutifully bounce off the pipework below and tell you where and how deep.
Great, I’ll take one – so what are the downsides?
Well the information doesn’t come up as a neon outline like is does on CSI – it comes up as a series of funny shaped black waves and these need to be interpreted by a trained and experienced operator to understand what the information actually means and therefore what the machine is trying to tell you.
Because GPR will bounce off all manner of solid objects, it’s important to be careful that you then spend a few days digging up a pipe as opposed to a buried power line which in turn means being able to interpret the subtle differences in the wave imagery that each object produces.
Other negative is cost – GPR machines currently cost the same as a brand new family car but frankly aren’t half as useful as they have quite a niche use and not much beyond that.
But for a competitive edge in the rat detection world that allows us to see and find what no-one else can, they are absolutely fantastic!
Pestology owns GPR machines and the surveyors are trained operators, so when we need it we’ve got it and can literally rewind time to find what got buried 50 years ago…