Providing Hydraulic Model and Evaluating Reliability of Water Distribution Networks (Case Study: Oshnaviyeh City)

Reliability is one of the important parameters in the process of design and operation of water distribution networks. Reliability index refers to the ability of the water distribution network to supply water with standard quality, sufficient quantity and within the appropriate pressure range for consumers under normal and abnormal operating conditions. Although many indicators have been provided by various researchers to evaluate the reliability of water distribution networks, so far this issue has not been taken into consideration by consulting engineers and water and wastewater companies in the design and operation of real water distribution networks. In this study, after preparing a calibrated hydraulic model for water distribution network of Oshnaviyeh city in West Azarbaijan province, the reliability of the mentioned network was evaluated. According to the results, the average reliability index of the water distribution network of Oshnaviyeh city during the day is 38.3, which means stressful operating condition. Examination of the reasons for the low reliability led to the identification of weaknesses of this network such as inappropriate diameter of some pipes, weakness in implementing pressure management program, inappropriate status of pipe loops and high amount of leakage (about 52 l/s). Improving the reliability of the studied water distribution network requires the implementation of rehabilitation and renovation programs based on the suggestions proposed in this paper. The results of this study showed that by evaluating the reliability of water distribution networks, existing weaknesses would be identified and their serviceability level would be improved and customer satisfaction would be increased.