Development of a Consequence of Failure Model and Risk Matrix for Water Pipelines Infrastructure Systems

Water utilities are finding it more cost-effective to practice a risk-based and data-driven proactive renewal planning to avoid extra costs from reactive repair and replacement. Risk is a function of the likelihood of failure (LoF) and the consequence of failure (CoF). This study conducted a comprehensive review of past studies on CoF and risk matrix, from both literature and practice to develop a better methodology for assessing CoF and developing risk matrix. The proposed CoF model enhances the triple-bottom line parameters and includes operational intelligence and renewal complexity in assessing CoF. Therefore, the model can overcome the limitation in the previous studies that considered only direct costs of a water pipeline failure. The proposed model develops a fuzzy inference system (FIS) to model system parameter interdependencies using IF-ELSE rules and incorporate heuristic knowledge in a “White-Box” approach, which is better than previous weighted approaches. The fuzzy logic approach is chosen due to better interpretability by decision-makers and the ability to capture water pipeline system uncertainty. This study also presents the limitations of traditional risk matrices developed previously and methods to overcome those limitations. The model and matrix will be verified and validated with multiple water utility datasets to check their robustness and accuracy in real-world conditions.