A holistic and integrated infrastructure system vulnerability assessment conceptual model

The increased number of manmade and natural disruptive and destructive events have increased concerns over the vulnerability of infrastructure systems. As existing assets age and citizens become more dependent on the services and products provided by these infrastructure systems, they reveal the lack of plans to protect infrastructure from potential threats and prompt the need to work on preparedness, response, and recovery plans to reduce the impact on service users. One of the challenges is to select and protect appropriate infrastructure from potential threats in the most efficient way, with limited resources, and not only by considering asset vulnerability but also user vulnerability. To accomplish these goals, decision-makers would benefit from data and information derived from more inclusive and holistic vulnerability assessment. Therefore this research will develop an approach to improve the decision making quality and reduce negative and costly consequences of disruptive events, through assessing the vulnerability of infrastructure systems by a more holistic approach. After a review of concepts and current methods available to assess vulnerability of infrastructure and identifying decision-maker’s needs, this thesis develops a conceptual vulnerability assessment model. This approach presents a broader infrastructure view, which will increase decision making quality in the light of current and emerging challenges. It also includes factors, and characteristics of infrastructure resilience, and downstream and upstream dependencies of a system. The outcomes and main distinctive features of this model are that it will extend the system boundaries and integrate users of the services provided by the system, or in other words “downstream dependencies”, as a factor in overall vulnerability assessment in order to give a more holistic view of infrastructure vulnerability. This concept also relates resilience factors directly into a vulnerability assessment model and provides a broader view to assess vulnerability of critical infrastructure. These distinctive features will provide more value based information for decision makers to decide more effectively. To bring together different vulnerability factors and system components “analytic hierarchy process” (AHP) is employed which is a first time for infrastructure system modelling. Ultimately these concepts have been demonstrated for a test case of a Water Supply System.