Behavioural-design-based risk assessment and mitigation against floods in historical urban built environment: a virtual reality approach

Risk-mitigation in historical Urban Built Environments (UBEs) should be designed by considering not only historical scenarios and hazard features but also their users and how they respond to emergencies. Flood is a critical disaster in historical UBEs, mainly in outdoor public spaces, essentially because of users’ interactions with floodwaters spreading in the complex and narrow urban fabric. A behavioural-design (BD) approach could support risk assessment and effectiveness evaluation of mitigation strategies since it relies on analyses of users’ emergency behaviours. This work is aimed at developing and verifying a novel approach to these tasks, by employing Virtual Reality (VR) and Serious Game (SG) criteria. VR allows representing and testing different UBE features, flood conditions and mitigation strategies in a sustainable manner. SG ensures a high volunteers’ engagement in tests. A module VR-SG tool is here developed and tested for a typical riverine historical UBE, involving more than 100 volunteers. Preliminary tests demonstrated how the approach provides results similar to those of real-world scenarios, while insights on how to improve the tool are also discussed. The proposed system can be used by stakeholders to preliminary assess risk and verify the impact of mitigation strategies under different scenarios before their implementation.