Modeling water pipe breaks - Three case studies

Municipal water infrastructure systems are in poor condition and are deteriorating rapidly. A general diagnosis of the actual structural state of these systems is needed, as are tools to assess their rate of deterioration. To make a diagnosis, one must collect and analyze data on the characteristics of water pipes and on their breakage histories. Unfortunately, many municipalities have only been rigorously recording breakage histories for a decade, while their pipes have been in the ground for much longer. A modeling strategy, inspired by survival analysis and using the annual number of water pipe breaks as an indicator of the structural state of a network, was applied to three municipalities characterized by their brief recorded pipe break histories. This paper presents a descriptive analysis of the water pipe and breakage data, and the application of the modeling strategy to these municipalities. Different replacement scenarios were also simulated to assess their impact on the evolution of the annual number of breaks in the three municipalities.