Implications of the Known Pressure-response of Individual Leaks for Whole Distribution Systems

Abstract

Previous experimental and numerical studies have shown that leaks in water distribution systems expand linearly with pressure under elastic conditions. The flow rate from such leaks as a function of the pressure head is described by FAVAD equation. The aim of this study was to investigate whether a combination of individual leaks displaying FAVAD behaviour can explain the typical range of leakage exponents found for distribution systems in field studies. For this purpose, a spreadsheet model was developed with typical distributions of leak quantities, areas, discharge coefficients and head-area slopes. Using a repeatability analysis, it was found that individual leaks displaying FAVAD behaviour can indeed explain the most commonly used leakage exponent of around 1 as well as the observed variation in leakage exponents between 0.5 and 1.5.