Assessing Public Perceptions of Blue–Green Infrastructure in Urban Watersheds: A Case Study of Acari River, Brazil

Accelerated urbanization and frequent flooding in contemporary cities have contributed to the devaluation of rivers within urban landscapes, resulting in a diminished relationship between residents and these waterways. Although there has been a notable increase in frameworks designed to enhance stakeholder engagement in flood risk management, these primarily target decision-makers, with limited focus on processes that ensure community participation in Blue–Green Infrastructure (BGI) initiatives. This paper seeks to address this gap by proposing a conceptual framework for assessing public perceptions of BGI in urban watersheds, particularly in areas facing socioeconomic vulnerabilities. The framework was applied through an online survey directed at inhabitants and experts associated with the Acari River Watershed, Rio de Janeiro, Brazil. The survey comprises five sections aimed at gathering respondent profiles, exploring their interactions with the case study, and eliciting their perceptions of BGI alternatives, supported by graphic representations. BGI alternatives were evaluated based on four principles: usability, reliability, feasibility, and acceptance. The findings indicate that while certain strategies were perceived as reliable, concerns regarding pollution and trust were significant, especially in densely populated areas. This framework is recommended for use in other urban contexts to facilitate effective community engagement in sustainable planning processes, especially in developing countries.