The purpose of trunk main leak detection is to find all the leaks that do not surface or come to the attention of the water utility on their large diameter trunk main network. The detection process involves teams of skilled leak detection technicians using advanced correlation devices. This may be in response to an increase in the minimum night flow (MNF) if the area is sectorised into a DMA or Water Supply Zone or simply as part of a proactive regular inspection schedule.

Many technologies for trunk main leakage detection utilise acoustic principles to identify and pinpoint leak locations. A pressurised water pipe will create a unique acoustic signature at the leak location due to the pressure differential between the inside and outside of the pipe—the water main acts as a medium for transmitting the acoustic signature of the water leak.

When water is escaping the pipe under pressure, it makes a distinct ‘hissing’ sound that can carry significant distances along the length of the water pipe and be detected on nearby service connections, hydrants or stop valves. Several factors influence the distance which the leak can travel but are primarily the pipeline material and diameter.

Aqua Analytics uses the most advanced leak noise correlator available to complete their trunk main leak detection work. This correlator is from the world’s leading leak detection equipment provider.

Trunk mains, typically assets that are over 300 mm in diameter, require a different approach to reticulation assets when it comes to leak detection. These are often assets critical to operations, and the current condition and presence of leaks must be well understood to reduce the likelihood of failure.

Trunk main correlators – specialised hydrophones or accelerometers are placed on the trunk main (typically at 1-2 km spacings), listening for specific frequencies and applying traditional correlation equations to detect the presence of leaks.

Trunk main leak detection is challenging due to the reduced sound propagation in larger diameter pipelines. Many utilities avoid trunk main leak detection activities due to a perceived lack of leakage on these assets; however, many examples in Australia and New Zealand prove this is inaccurate. Aqua Analytics can deliver trunk main leak detection using the following solutions:

Free-swimming leak detection technologies – a cylindrical device is inserted into a live pipeline, propelled by the water flow, and is captured downstream. The captured data is downloaded, analysed, and the leak location is determined.

Tethered leak detection technologies – a device is inserted into a live pipeline, attached to a long cable, and propelled by the water flow. An operator will listen for the acoustic signal from the device hydrophone and determine if any leaks are present.

Real-time trunk main monitoring – specialised hydrophone devices can monitor large diameter pipelines in real-time for changes in operating conditions that may indicate a new, developing or growing leak.

The Aqua Analytics team consists of internationally renowned experts on water leakage reduction, non-revenue water (NRW), and acoustic leak detection methodologies. Over several decades, we have developed customised water loss reduction strategies for conditions in Australia and New Zealand to ensure we achieve lower levels of water loss. We are viewed as leaders in trunk main leakage detection through our long-term engagements on projects in Sydney, Melbourne, Adelaide, Brisbane and throughout New Zealand.

We also pride ourselves on delivering excellent customer service and finding solutions to problems where others cannot. If you are looking to achieve results from your active leak detection project,  please contact us today by giving us a call, or through the enquiry form below.