Is this resilient enough? Including users’ acceptance levels into the critical infrastructure resilience assessment

This study presents a new perspective on the resilience assessment of critical infrastructures by proposing a framework which includes the desired level of resilience. Including the users’ perspective in this resilience assessment is essential, and a method how to do this is provided. The method is applied in a case study in an urban environment and successfully demonstrates that including the users’ perspective is a viable strategy, offering promising insights to researchers and policy makers.
The proposed method consists of three steps to include the users’ tolerance levels in the resilience assessment. The first step is the resilience assessment, which aims to quantify resilience in terms of number of people affected by the disruption. This is done by simulating different rainfalls in a 3Di hydrodynamic model and spatially comparing them with critical infrastructure and population data. The second step analyses the users’ acceptance levels to disruption, which can be seen as the resilience of the users and is quantified in the share of people who do not accept posed disruption. A questionnaire-based approach is carried out using ordinal regression to analyse the data. The last step combines the outcomes of the previous steps and establishes the number of people unwilling to accept disruption. Dimensions included in this assessment are 1) Severity of the hazard; 2) Recurrence time of the hazard; 3) Type of infrastructure network; 4) Number of people affected over time; 5) Acceptance levels to disruption over time.
Findings of the study indicate that within the study area the risks of not accepted disruption is relatively low. The research gives input to what a norm could be for a desired level of resilience. Furthermore it demonstrates that in proposing measures to improve resilience of networks, the resilience of the user should not be overlooked.