Speaker
Description
Water distribution systems can experience high levels of leakage, originating from different sources, such as deterioration due to aging of pipes and fittings, material defects, and corrosion [1]. In addition to causing financial losses and supply problems, leakages in treated water distribution also represent a risk for public health. Nowadays, several techniques for leak detection have been investigated, such as acoustics, based on the detection of the noise produced by a leak in pressurized pipes, thermography, looking for changes in the soil temperature, and time domain reflectometry, looking for changes in the effective dielectric permittivity of the soil. Several factors, including the environmental noise, the geometry and composition of the pipes, the soil composition, the presence of tarmac on ground, etc., can limit the use these techniques.
We are investigating the possibility of using cosmic ray (CR) neutrons for the leakage detection in water distribution: fast and epithermal CR neutrons, penetrating the soil, can be thermalized, mainly by means of collisions with hydrogen atoms, and diffuse back into the atmosphere. As a result, the flux of low-energy neutrons above the soil is inversely correlated with the hydrogen content of the soil, and in turn with the presence of water [3]. This mechanism has already been investigated in other contexts such as agriculture [4], catchment hydrology [5], snow hydrology and more with encouraging results.
In this talk, we present a feasibility study of the technique, based on Monte Carlo simulations, and an overview of the neutron detector, currently in late stage of development, which will be used for the first experimental measurements.
References:
[1] AWWA (1999), “Water Audits and Leak Detection”. Manual of Water Supply Practices No. M36, 2nd Edition, American Water Works Association, Denver, CO, 99 pages.
[2] A. Cataldo et al. (2016), “Accuracy improvement in the TDR-based localization of water leaks”. Results in Physics, Volume 6, 594-598, https://doi.org/10.1016/j.rinp.2016.08.012.
[3] M. Zreda et al. (2008), “Measuring soil moisture content non‐invasively at intermediate spatial scale using cosmic‐ray neutrons”, Geophysical research letters 35, 21.
[4] C. Finkenbiner et al. (2019), “Integration of hydrogeophysical datasets and empirical orthogonal functions for improved irrigation water management”, Precision agriculture 20.1, 78-100.
[5] B. Fersch et al. (2018), “Synergies for soil moisture retrieval across scales from airborne polarimetric SAR, cosmic ray neutron roving, and an in situ sensor network”, Water Resources Research 54.11, 9364-9383.
| Topic | Applications |
|---|
