Hydraulic risk assessment of water distribution systems

Abstract

The existence of uncertainties in water distribution systems (WDSs) has been recognised for several decades within the literature (typical examples of uncertainty include demand variability, component failures and increased roughness of pipes). The existence of these uncertainties implies that the risk of inadequate hydraulic performance needs to be identified and assessed throughout the system. In this paper, the risk of hydraulic failure of an existing WDS is assessed, both in terms of reliability (probability of non-failure) and vulnerability (probable magnitude of failure given that a failure has occurred). The WDS considered within this paper is the McLaren Vale/McLaren Flat system, which is located approximately 30 km to the south of Adelaide, South Australia. The spatial variability of both reliability and vulnerability is modelled and the results are presented using spatial contour maps. The results indicate that such maps are extremely useful for identifying and interpreting critical regions and regions of poorer performance in terms of pressure head. Furthermore, by using both reliability and vulnerability indices, a more complete description of risk, using the multiple criteria, is obtained.