The impact of the choice of the probability distributions of random parameters on evaluation of water distribution network reliability

During recent years several methods based on the probabilistic approach are proposed for the analysis of the performance of water distribution systems. Uncertain elements are described by probabilistic laws chosen on the basis of the analyzed network characteristics. However the choice of the more suitable probabilistic distribution and of the statistical parameters can be difficult because of the lack of information about the water distribution system. In this paper the impact of changes of the probability distributions of some random variables on evaluation of water distribution network reliability is analyzed. This analysis allows to quantify the effect of any errors that may occur in the probabilistic characterization of random parameters. The study is performed using a technique capable of considering the mechanical failure of the network components, the spatial and temporal variations of the water demand and the uncertain distribution of the pipe roughness.