Pressure dependent stochastic reliability analysis of water distribution networks

Any reliability analysis based on just deterministic values of daily average or peak demands, cannot represent the overall system reliability realistically. Using a stochastic model in this paper variations of the system and nodal reliability values are investigated through a period of time. Considering probabilistic nature of demands, this paper combines the extended period simulation of water distribution networks with the head driven simulation based reliability analysis that presents the nodal and system reliabilities more realistically than conventional demand driven simulation based analysis. A sample network with possibility of one link failure is examined and diurnal profile of reliability values due to mechanical and hydraulic failures and known probabilities of demands is presented. It is seen that considering the probabilistic nature of demands the severity of mechanical and hydraulic failures on the hydraulic performance of the system are illustrated properly and realistically, especially at the critical times or nodes, in comparison with the deterministic values.