Reliability assessment of the Nonsan distribution network by the method of Ozger

The importance of water distribution network reliability is continuously growing nowadays in South Korea in order to improve the level of service to the consumers. The distribution network in the city of Nonsan occasionally experiences insufficient pressures and water quality problems. The reliability assessment of this network was performed according to the method of Ozger. The computer programme developed with EPANET Toolkit functions in Visual C++ language based on this method, conducts the Pressure-Dependent Network Analysis (PDNA). For more realistic assessment, the model network was analysed under the assumption of single pipe failure and with extended-period simulations for various ‘what-if’ scenarios. Prognosis of the reliability was established by using the life distribution models, which can describe an increase of pipe failure rates. According to the results, the reliability of the system is presently considered as satisfactory but the deterioration of the situation can be expected within a period of 10-15 years.