Factors affecting the costs and timing of water main replacement in a water distribution network

Abstract

Deteriorated cast iron pipes often account for a significant portion of water main failures in a water distribution network. Such incidents cause havoc to traffic circulation, damage surrounding properties and public infrastructure, and increase the risk of water contamination. Thus, infrastructure managers often receive questions from stakeholders concerning the replacement time horizon of such pipes and the associated financial investment needs. These questions are difficult to answer as the service lifetime of buried pipes depends on a number of factors such as the rate of deterioration, the associated failure risk, the level of risk tolerance of the utility as well as the intervention planning activities of other utility networks. In addition, replacement costs depend on economies of scale as the unit cost of pipe replacement tends to decrease as length increases. Managers must consider these factors along with associated uncertainty when making estimates on replacement projections of problematic pipes. In this paper, a methodology is presented that aims to help infrastructure managers make accurate pipe replacement projections. An example is provided of the implementation on a large water distribution network.

Asset management analytics for urban water mains: a literature review

“…The probability of failure could be used by municipalities to optimally manage their annual rehabilitation plans. Many studies apply machine learning models to pipes that have had breaks (Harvey et al 2013;Shirzad et al 2014;Sattar et al 2016;Kutyłowska 2017;Kerwin and Adey 2018). Robles-Velasco et al ( 2020) considered all pipes rather than just those which had experienced breaks.…”