Effectiveness of a Dam-Breach Flood Alert in Mitigating Life Losses: A Spatiotemporal Sectorisation Analysis in a High-Density Urban Area in Brazil

Abstract

The integration of early warning and evacuation systems (EWES) with estimations for mitigating the loss of life in flood risk assessments marks an advancement towards developing robust emergency action plans for dam breaks. Through the simulation of diverse EWES scenarios, the impact of these systems, coupled with community preparedness, on minimising the potential for loss of life could be calculated. This study was conducted in the theoretical context of a dam break located upstream from a densely populated urban region in Brazil. Hydrodynamic and agent-based models were utilised to estimate potential loss of life across various scenarios and simulations. The Monte Carlo approach, in combination with the LifeSim model, was applied to assess how factors such as warning issuance timing, evacuation strategies and community responses impact the model’s outcomes. Sensitivity analysis was performed considering the overall exposed area and specific areas at risk for different spatiotemporal EWES strategies. The results of simulations highlighted the EWES’ great potential for risk mitigation and displayed optimal times for warning issuance. The warning diffusion and the protective action initiation parameters proved crucial for improving EWES. The spatiotemporal sectorisation of the alert and evacuation was also an effective strategy to optimise EWES. This methodology should allow for further similar tests and incite EWES improvements based on consistent loss of life alleviation simulations.

Probabilistic mapping of life loss due to dam-break flooding

“…In general, early warning systems, evacuation plans, and population preparedness positively affect emergency management, thereby significantly reducing the potential for loss of life (e.g. Lumbroso et al 2021;Silva and Eleutério 2023b). (f) Flood exposure is in constant evolution and can vary in the medium-and long-term due to new urbanizations and changes in demographics and land use in the study area (e.g.…”

“…A comprehensive analysis of dam-break flooding consequences should consider the population at risk within the potentially flooded area, along with societal, economic, and environmental impacts (Sun et al 2014;Sarchani and Koutroulis 2022). However, since loss of life is the most severe consequence of a catastrophic event such as flooding (Silva and Eleutério 2023b), preventing loss of human lives is the main concern in emergency management following a dam failure. For this reason, this paper focuses on this aspect of the flooding damage.…”

Simulation of Flood-Induced Human Migration at the Municipal Scale: A Stochastic Agent-Based Model of Relocation Response to Coastal Flooding

“…Agent-based modeling (ABM) provides an alternative mechanism to represent heterogeneous decision-making processes and human responses to natural disasters where individual-level variation in behaviors leads to emergent collective outcomes, such as evacuation [27][28][29][30] and migration [31,32]. Numeric simulations of multi-agent systems can capture effects stemming from heterogeneity across different types of actors [33].…”