AWWA CSC91089

This paper shows an application of reliability theory in modeling the deterioration of water distribution systems. The proposed approach is based on a simple reliability measure defined in terms of pipe reliability and source-to-node connectivity. Previous published work has concentrated on the theoretical aspects of the subject. Thus, rather than introducing the mathematical jargon, a case study is presented in a tutorial style to emphasize the application rather than the theory. The proposed approach is easy to program and implement on personal computers and is suitable to analyze networks of arbitrary shapes. Finally, deficiencies of the method are identified and recommendations are made for improvements and future research. This technique combines deterioration characteristics of pipes and topological features of the network and aids in prioritization of pipe replacement. Reliability of the model is increased by factoring in a pipe importance factor (PIF), which combines age, break rate, reliability, and geometry into one factor. Rankings based on other deterministic factors, such as replacement costs, number and importance of beneficiaries, hydraulic performance, and pavement improvements should be incorporated with PIF rankings. For example, replacement of a high PIF pipe might become even more desirable if hydraulic network analysis indicates that replacing it with a larger diameter pipe will improve the fire fighting capability in its service area.