Algorithm for Assessment of Water Distribution System's Readiness: Planning for Disasters

Water distribution systems are one of the most important infrastructures in urban areas. The objective of every urban water distribution system is to deliver enough water of acceptable quality with adequate pressure to different demand points. There are many interruptions and occasional disasters that impact the performance of the water distribution system, some of which could be quite devastating. The most common disasters are main breaks that may cause considerable water losses and bring up the system to partial or complete shutdown. Evaluation of the state of the system's readiness helps managers make better decisions to prevent disasters and respond better to emergencies. In this paper, the state of the system's readiness in dealing with disasters has been quantified using a hybrid index called the system readiness index. This index is developed based on the combined effects of three system performance indexes, namely reliability, resiliency, and vulnerability. They are combined through hydraulic characteristics of the network at some critical nodes of the water distribution system, using a neural network model. Different failure scenarios are defined to evaluate the system performance and to analyze the systems interruption. A Bayesian approach for updating the probability of failure is used to incorporate the new information on the state of the system. The proposed algorithm is applied to a part of the water distribution system of the Tehran metropolitan area in Iran. The results show the significant value of the proposed algorithm in helping the decision maker to improve the system's performance and develop contingency plans when faced with disasters.