RELIABILITY-ANALYSIS OF WATER DISTRIBUTION-SYSTEMS UNDER UNCERTAINTY

In most of the developing countries, the Water Distribution Networks ( WDN) are of intermittent type because of the shortage of safe drinking water. Failure of a pipeline(s) in such cases will cause not only the fall in one or more nodal heads but also the poor connectivity of sou rce with various demand nodes of the system. Most of the previous work s have used the two-step algorithm based on pathset or cutset approach for connectivity analysis. The computations become more cumbersome wh en connectivity of all demand nodes taken together with that of supply is carried out. In the present paper, network connectivity based on t he concept of Appended Spanning Tree (AST) is suggested to compute glo bal network connectivity which is defined as the probability of the so urce node being connected with all the demand nodes simultaneously. Th e concept of AST has distinct advantages as it attacks the problem dir ectly rather than in an indirect way as most of the studies so far hav e done. Since the water distribution system is a repairable one, a gen eral expression for pipeline availability using the failure/repair rat e is considered. Furthermore, the sensitivity of global reliability es timates due to the likely error in the estimation of failure/repair ra tes of various pipelines is also studied.