Cascading failure analysis in order to assess the resilience of a water supply system

Drinking Water Supply Service is considered vital in all societies, modern and old. As for all vital services, governance undertakes all possible measures to guarantee their supply continuity. However, severe service supply disruptions may occur under the action of threats, series of failures cascading or any combination of them. Threats may be nature originated: climatic extreme conditions, earthquakes, floods. It may also be man originated: ill-informed managing actions, organisational misconduct or malevolence. As for failures, it can be humans or simply systemic: unproven technology, fatigue, ageing, overloading or operational hazards. Whatever the origins of the disruptions, societies conceive legislations, standards and processes in order to enhance the resilience of the vital service supply systems and the correspondent critical infrastructures. They provide appropriate R&D frames and assets, amongst others, in order to conduct activities on critical infrastructures resilience modelling, simulation and analysis (MS&A). The paper contributes into the development of a resilience concept and a methodology for integrating cascades of failures to help in crisis management decision making. The proposed methodology is applied on a case study belonging to the drinking Water Supply Services and its critical infrastructures.