How to Ensure Accurate Underground Water Leak Detection?

By superadmin on January 17, 2019 in Blog

Aside from wasting water, leaks are also destroying underground assets (e.g. supporting structures, pipe breakage, transportation systems), which is why it’s important to promptly locate the leak and do so accurately.

One way to accomplish that is with the use of Ground Penetrating Radar (GPR). It works by emitting electromagnetic radiation (in the microwave band) and then detecting the reflected signals from subsurface structures. As you might have realised, this is a non-invasive procedure of knowing what’s underneath a site. This gets rid of unnecessary digging (which destroys surface infrastructures) and results to faster leak detection and verification.

Back then acoustic leak detection methods were being used. But the GPR method is gaining widespread popularity because of its reliable response to changing electrical properties (the accuracy of many detection methods depends on the reflected signals). For instance, the GPR method provides a good response as a function of soil, rock material and moisture content. There are interferences but the GPR method remains to be superior because of its accuracy, speed and cost efficiency in detecting underground leaks.

How Ground Penetrating Radar works

As mentioned it’s about emitting radiation and then reading the reflected signals. The reflected signals (or the refracted and scattered signals) then will be received by an antenna. This receiving antenna records the variations in the return signal. The variations are due to the different permittivities (related to the formation of an electric field in a particular medium) of materials as the radiation encounters a boundary or a buried object. The mechanism is similar to how the familiar radar works. The device emits a signal and then the return signal is interpreted to provide useful information that people can understand (e.g. a visual map). As a result, interpreting the return signal will give information on the structural variation underground and the condition of the medium as well.

How is this useful for underground water leak detection then? The GPR method is useful in detecting underground voids (earlier we mentioned the subsurface structural variation). The voids might have been created by the leaking water as it spills and erodes the surrounding materials. The method is also useful for detecting the anomalous changes of the materials underground (take note that electric properties and the return signal will change if something happened).

Aside from accuracy, the Ground Penetrating Radar method has become the practical choice because of its flexibility. It can work on detecting both metal and plastic pipes. In contrast, acoustic leak detection methods often encounter problems when working with plastic pipes. But with the GPR method, those problems are eliminated and the team only requires one method to do the job.

Many professionals has also used the GPR method when detecting subsurface infrastructures and underground leaks in high-traffic and crowded areas. In addition, the GPR signals can be rapidly collected and interpreted so that contractors could immediately resume to work. This then results to better cost effectiveness because of the higher speed (detection can be completed faster and the resulting lower labour costs).

Limitations of the GPR method

The GPR method is now being widely used in identifying leaks in buried water pipes (by detecting underground voids or material changes). However, there are still important considerations that may affect its accuracy and reliability.

For example, some soils such as clay have a high conductivity which prevents the GPR signal from penetrating the soil. It’s a similar case with saline soils where there’s large amount of salts and ions. These can interfere with the analysis because as mentioned earlier the GPR method relies on response to electric properties of the material and medium.

These issues can be overcome by using a complementary method (e.g. CCTV underground inspection), digging a test hole for verification and with the right use of expertise and technology. Experienced locators can readily anticipate the interferences and problems because they’ve already worked in various sites. Also, they’re already familiar with the underground structures and they can determine immediately if a certain method is appropriate for the application.

Although the GPR method is good enough for most applications, it’s still important to dig a test hole to verify the location of the utility line and leak. The GPR method can provide the initial information on where to dig that test hole and then once the partial digging has been performed, contractors can then now fix the leak.

Proactive underground water leak detection and prevention

Damages from water leaks can be very costly especially if massive volumes of water have been already released. Aside from the waste of precious water, the leakage can result to soil and material erosion, corrosion and ruin of underground assets (pipes, other utility lines, supporting structures).

As a result, many take the proactive approach in detecting the water leaks before they can become worse. That proactive approach also includes timely inspection to prevent the water leaks from happening in the first place.

In this case underground CCTV inspections are useful in locating the problems early on. The advanced mobile camera technology enables us to record the exact locations and conditions of all subsurface infrastructure, pipes which have damages or blockages and the shape and layout of pipework (including the junctions and bends). The mobile camera technology can even see hard to access areas such as boreholes, wells and beyond the bends and junctions.

Pipes naturally deteriorate due to the chemical interactions underground. It’s especially the case with metallic pipes wherein corrosion can make the infrastructure vulnerable (the environment underground can be rich in iron, moisture and oxygen). Also, recent structural projects might have caused the pipes to shift or the soil above to collapse. This can then result to a blockage or damage that would block the water and pressurise it (eventually a leak might result from this).

It’s important to know regularly the conditions of the pipes. This way, we can know if it’s time for replacement or upgrade of the subsurface infrastructure. This also helps in preventing costly damages on the underground assets including the pipework and other surrounding utilities and structures.

Underground water leak detection services

Here at One Search Locators we have promptly detected leaks in underground water pipes. Our service area covers Sydney, Newcastle, Wollongong, Melbourne and surrounds. We understand that water leaks can be very costly in terms of repairs and surrounding infrastructure damages, which is why our certified Service Locators and our team arrive on site within 24 hours upon the client’s request.

We effectively use Ground Penetrating Radar and complementary technologies to detect the water leaks underground. Although GPR itself is highly accurate and reliable, we use our technical expertise to acquire a more accurate reading and ensure that the results are consistent. This way our clients can perform the necessary repairs and upgrades to the subsurface infrastructure (and do so with accuracy).

The subsurface infrastructure is highly complex especially in urban areas. In fact what’s underneath can be more complex than the highrises and crowded cities above the ground. As a result, inspecting the subsurface infrastructure and determining the problems require a high level of expertise.

Many companies contact us here at One Search Locators for those kinds of work. Whether it’s locating a buried utility or performing a comprehensive inspection (underground CCTV inspection) of the underground pipes, sewer lines, drains and conduits, our team can help you promptly identify a potential problem by providing comprehensive information about the pipework and utility infrastructures underground.

Contact us here at One Search Locators for a prompt water leak detection underground (GPR method and other electromagnetic technologies) or proactive leak prevention (e.g. underground CCTV inspection). Time is money which is why we will arrive at your site within 24 hours upon your request. We do the inspections and interpretations fast so we can help prevent worse and more costly damages to the subsurface infrastructure. With the modern tools we use and our technical expertise, you can be sure of the accuracy and promptness of the results.