Selection of a Coastal Protection Measure via Multi-Criteria Decision Analysis: The Case of Balneário Camboriú, Brazil

The present study applies a hybrid Multi-Criteria Decision Method called Multicriteria Instant Runoff Voting (MIRV) to select the most appropriate coastal protection measure for Balneário Camboriú, Brazil, a city that is highly vulnerable to rising sea levels. MIRV combines the features of Instant Runoff Voting and the Borda method to integrate multi-criteria assessment while addressing the monotonicity shortfall of traditional voting systems. The research engages a multidisciplinary team of seven professionals to evaluate seven coastal protection alternatives against 11 criteria, including implementation cost, environmental impact, social impact, and adaptability. The results identify Submerged Artificial Reefs (SAR) as the most suitable measure, balancing protection with ecological and social benefits. Sensitivity analysis confirms the method’s robustness despite varying decision-maker preferences. MIRV demonstrates a scalable, intuitive framework that accommodates diverse stakeholder inputs, facilitating decision-making in complex scenarios. This approach can be extended to similar challenges globally, offering a practical solution for integrating scientific rigor and stakeholder values in environmental planning.