UNSW leak-detection tech could save billions of gallons of water

Patented sonar array optical technology developed at UNSW Sydney will be tested in Sydney Water’s pipe network to determine its capacity to accurately pinpoint leaks. It is hoped that the technology will efficiently detect leaks in the network to address the estimated 10% of water lost daily from Sydney Water mains, with the potential to save billions of gallons of water each year.

Funded by Sydney Water, Professor Francois Ladouceur from the UNSW School of Electrical Engineering and Telecommunications and his team (partnered with Thales Underwater Systems and Zedelef) confirmed the viability of their technology for ocean monitoring in successful trials conducted at Lake Macquarie last year. For the Sydney Water trial, they will place their sonar array in a water main and then simulate a leak, which Prof. Ladouceur expects they’ll be able to pinpoint accurately.

“Our sonar array is like a 50-metre strip of garden hose with 16 microphones inside it, equally distributed along its length,” explained Prof. Ladouceur. “These microphones detect the smallest of sounds and we use a single optical fibre to send all this information back to dedicated software that computes where a leak is located.”

Sydney Water currently uses a variety of approaches to detect leaks within its network of over 22,000 km of pipes, including monitoring rainfall and soil moisture levels, pipe inspections and acoustic listening devices. These methods can be costly and difficult to deploy over such a large network.

“The incumbent acoustic approach requires copper wires running to and from each microphone to physically connect to the data collection head-end [collection point] where computer software interprets the signals coming from the network,” Prof. Ladouceur explained.

“This isn’t too bad if you only have a few microphones, but if you want an array over say 100 microphones or more to cover a larger portion of the network, you’ll end up with a bundle of 200 wires, which will quickly become very expensive, heavy and unwieldy.”

The UNSW professor said the use of optical technology allows the bulky bundle of wires to be replaced with a cheaper, lighter and more durable single optical fibre.

Prof. Ladouceur’s trial is part of a wider project being led by the NSW Smart Sensing Network (NSSN), also funded by Sydney Water and other utilities. The NSSN is bringing together five Australian universities to test emerging technologies to identify leaks and potential failures in water supply networks.

Prof. Ladouceur and his team hope that this project will provide the basis for the development of the next generation of leak detection at Sydney Water. Large areas of the water network could be regularly inspected with the design of a longer sonar array, or robots could be used to drag arrays over vast distances through the pipes to listen for leaks. The end goal is to cover as much of the water network as possible to detect and fix leaks, thereby preventing further losses of arguably our most valuable natural resource.

“If the economics work out, our technology could be laid down inside of all new pipes as they’re being built, and then they will have permanent leak detection,” Prof. Ladouceur said.

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