Modeling the Pressure-Leakage Response of Water Distribution Systems Based on Individual Leak Behavior

Pressure management has been used for more than 3 decades to reduce leakage from water distribution systems. While few of these studies have been published, information on the ranges of field study leakage exponents is available. In contrast, several studies on the pressure-leakage relationship of individual leaks have been published, and verified models have been developed for predicting the response of elastically deforming leaks. The main aim of this paper was to determine whether researchers' current understanding of the pressure-leakage response of individual leaks can be reconciled with the observed pressure-leakage response of district metered areas containing many leaks. To investigate this, a model of the distribution of individual leaks and their parameters was developed based on available literature and expert advice. A repeatability study showed that such a model can indeed produce typical distributions of leakage exponents found in field studies. A sensitivity analysis of the various parameters showed that the average system pressure and condition of the system had the greatest influence on the system leakage exponent. Finally, it was shown that a small fraction of leaks with high leakage numbers (i.e.,in highly flexible material or closing under zero pressure conditions) can explain the high background leakage exponents often found in systems with only background leakage.