Water pipe monitoring via fiber optical sensor and ground penetrating radar: a joint laboratory experiment

Effective usage of water resources is a relevant topic to move towards smart and resilient cities, and it demands technologies aimed at monitoring water distribution networks at avoiding wastefulness and assuring environmental safety.

In this frame, research activities designing technological solutions assuring time-constant monitoring and, simultaneously, providing high spatial resolution images from which infer accurate information about the position and extension of the leakage are carried out.

Being this request difficult to be satisfied by means of a single sensor, the pursued idea is the joint and cooperative use of the distributed optical fiber sensor based on the Brillouin scattering phenomenon [1] and the microwave tomography (MWT) enhanced ground penetrating radar (GPR) [2]. The first technology, if integral to the pipe, is able to detect temperature and/or thermal conductivity variations occurring in the soil hosting the pipe and due to water leakages. Therefore, it appears suitable to assure continuous monitoring and to provide low spatial resolution information about leakage detection. Conversely, GPR allows on-demand non-invasive surveys providing high spatial resolution images of the investigated scenario, if the collected raw data are processed properly. An effective way to do it is the use of MWT approaches, which face GPR imaging as an inverse scattering problem [3].

In order to provide a proof of concept assessing the benefits and limits of the cooperative use of the above technologies, a joint experimentation was carried out. Specifically, an ad-hoc experimental scenario allowing to reproduce a water leakage was built. The scenario is a scaled reproduction of a realistic test case and a plastic pipe filled with fresh water and buried in a river-sand terrain makes it up. The optical fiber sensor was buried in the sand few cm underneath the pipe, while GPR data were collected along and across directions with respect to the pipe.

The achieved results confirmed the expected potentialities and encourage going on this activity.

A detailed presentation of the experimental setup and the achieved results will be provided at the conference.

Acknowledgment: The authors would like to thank the SMART WATERTECH project “Smart Community per lo Sviluppo e l’Applicazione di Tecnologie di Monitoraggio e Sistemi di Controllo Innovativi per il Servizio Idrico Integrato” by which the present work has been financed.

 

[1] Bernini R., Minardo A., Zeni L. (2004) Accuracy enhancement in Brillouin distributed fiber-optic temperature sensors using signal processing techniques, IEEE Photonics Technology Letters 16 (4), pp. 1143-1145.

[2] Catapano, I., Gennarelli, G., Ludeno, G., Persico, R., Soldovieri, F. (2019). Ground Penetrating Radar: Operation Principles and Data, Wiley Encyclopedia of Electrical and Electronics Engineering.

[3] Catapano, I., Palmeri, R., Soldovieri, F., Crocco, L. (2022). GPR Water Pipe Monitoring and Leaks Characterization: A Differential Microwave Tomography Approach. In: Di Mauro, A., Scozzari, A., Soldovieri, F. (eds) Instrumentation and Measurement Technologies for Water Cycle Management. Springer Water. Springer, Cham.