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What We Did
Dr. Derek Li and his team are investigating sound wave based non-intrusive technologies for condition assessment of buried water supply networks. These technologies leverage from similar mechanisms as bats and dolphins, which use the reflection and transmission of actively generated sound wave signals in pipelines to detect and pinpoint pipe wall deteriorations and faults, such as leaks and blockages. In 2020, Dr. Derek Li and his team revolutionized their technology into the next generation, using the ambient noise generated by turbulence flow in water supply networks as natural signal sources for assessment.
This new technology avoids the sunstaintial power consumption, expensive devices and manpower involvement in active sound wave generation. It can be achieved by passively listening to the ambient noise in water pipelines using automated, low-power and low-cost pressure sensors. These sensors will be linked via wireless communication technologies into a wireless sensor network, achieving a large-scale, real-time and non-intrusive condition assessment and fault detection for our aging water supply network.
Dr. Derek Li and his team have applied this technology to some of the operating water supply networks in Christchurch city and Waimakariri district. Hidden pipeline deteriorations and faults were successfully diagnosed and localized in these preliminary applications.
Who Was Involved
Prof. Pedro Lee, Waimakariri district council, Christchurch city council
Why It Matters
Water supply systems transport a precious resource but the much of NZ systems are beyond their design life and desperately needing replacement. The condition of the ageing pipelines is largely unknown, leading to ineffective investment and severe water supply losses. Over 20% of our drinking water is being lost through buried deteriorated pipes along with an increasing risk of water contamination from pathogen intrusion and asbestos from decaying pipe wall. However, the inaccessibility and the expanse of buried pipeline networks pose challenges to current assessment technologies, which mainly rely on intrusive and destructive physical inspections such as cameras insertion or pipe wall sampling.
Learn More
Wang, W., Li, Z., Dubey, A., Lee, P., Fink, M., & Murch, R. (2021). Passive imaging of water pipelines using ambient turbulence noise. Mechanical Systems and Signal Processing, 160, 107882.
