Flood risk management in Sint Maarten – A coupled agent-based and flood modelling method

Abstract

Disaster risk reduction is a major concern of small island developing states. Measures to reduce risk should not only be based on the magnitude of physical hazard, but also on the exposure and vulnerability of communities. In this article, we examine flood risk management policies in the Caribbean island of Sint Maarten using coupled agent-based and flood models. The agent-based model is used to model actors' behaviour in relation to urban building development and policies that are designed to reduce flood hazard and communities' vulnerability and exposure. The policies considered in the model are a Beach Policy, a Building and Housing Ordinance, a Flood Zoning policy and hazard mitigation structural measures. The flood model is used to simulate coastal and pluvial floods on the island. Agent behaviour such as building new houses and implementing hazard reduction measures affect the flood model as these actions affect the rainfall-runoff process. The flood maps generated from the updated flood model simulations are then used to assess the impact and update agents' attributes and behaviour. The simulations results show that low-lying areas are populated, which increases the exposure, and the number of vulnerable houses is also high. Hence, out of the four policies, implementing hazard reduction measures is the most important. Reducing the flood hazard by widening existing drainage channels, constructing new ones and building dykes as coastal flood defence would reduce the hazard, hence reducing the number of flooded houses. As it affects all households on the island, the Building and Housing Ordinance is an important policy to reduce vulnerability. In general, the coupled model outputs can be used to inform policy decision making and provide insights to policymakers on the island.

Capturing flood-risk dynamics with a coupled agent-based and hydraulic modelling framework

“…Tonn and Guikema (2017) investigated different mitigation strategies at community and individual levels using statistical flood-level data. Abebe et al (2018Abebe et al ( , 2019) developed a new framework for integrating a hydraulic model into an ABM to represent individual and institutional decision making during flooding.…”

The role of household adaptation measures in reducing vulnerability to flooding: a coupled agent-based and flood modelling approach

“…More specifically, this paper extends two studies presented in Birkholz (2014) and Abebe et al (2019b). Birkholz qualitatively explored PMT to study household flood preparedness behaviour in the German city of Hamburg.…”

“…Adding local knowledge of flood risk management (FRM) issues and using other data sources, we extended the previous work by developing a simulation model that could support decision-making. Furthermore, the study has extended other prior works (Abebe et al, 2019b;Erdlenbruch and Bonté, 2018;Haer et al, 2016) to study human-flood interaction better and to gain new policy insights. With all the extensions, we have demonstrated that coupled ABM and flood models, together with a behavioural model, can potentially be used as decision support tools to examine the role of household adaptation measures in FRM.…”

“…The current study uses the qualitative study as a base to conceptualise and further explore the household flood preparedness behaviour in Hamburg using an ABM. Abebe et al (2019b) employ the coupled floodagent-institution modelling (CLAIM) framework developed in Abebe et al (2019a) to conceptualise the agent-flood interaction by decomposing the system into five components -agents, institutions, urban environment, physical processes and external factors. Their main focus was to study the implications of formal rules as institutions.…”

Tracing resilience, social dynamics and behavioral change: a review of agent-based flood risk models

“…Alternatively, location-specific fixed flood maps (Dubbelboer et al, 2017;Haer et al, 2017) are used for different return periods, for example, 1:100 flood. Finally, there are examples of articles belonging to the SH group that employ hydrologic models (Abebe et al, 2019a(Abebe et al, , 2019bHaer et al, 2019Haer et al, , 2020Löwe et al, 2017;McNamara & Keeler, 2013;Michaelis et al, 2020). Despite the increased complexity of coupling engineering and socio-economic models, hydrologic models' presence establishes a two-way feedback between human and natural systems.…”