Researchers to locate Sydney water leaks using optical sonar array tech

Researchers at the University of New South Wales (UNSW) Sydney have received funding from Sydney Water to test the ability of optical technology to detect water leaks.

Sydney Water has provided funding to Professor Francois Ladouceur from the UNSW School of Electrical Engineering and Telecommunications and partners from Thales Underwater Systems and Zedelef to test whether their patented optical sonar array technology can accurately detect leaks in Sydney’s water network.

According to the university, an estimated 10% of water is lost every day from Sydney Water mains, and it is hoped this technology could save billions of gallons of water annually.

“Our sonar array is like a 50-metre strip of garden hose with 16 microphones inside it, equally distributed along its length,” explained 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.”

As part of the trial, the researchers will place their sonar array in a water main and then simulate a leak, which they hope to be able to pinpoint accurately.

Sydney Water currently employs a range of technologies to detect leaks, including monitoring rainfall and soil moisture levels, pipe inspections and acoustic listening devices. However, these methods are often expensive and difficult to deploy over the utility’s 22,000km 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,” added Ladouceur.

“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 unwieldly.”

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

The ultimate goal of the project is to cover as much of Sydney Water’s network as possible to detect and fix leaks, preventing further water losses.

“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,” Ladouceur said.