Multidimensional evaluation of three rainwater retention basins in Brazilian Southeastern region

Abstract Inundation has become a recurrent issue in urban areas, highlighting the need for effective mitigation strategies. Various interventions have been implemented, underscoring the importance of systematically evaluating their long-term performance. This study presents a case analysis of three rainwater retention basins in Sorocaba, São Paulo, Brazil, applying a multidimensional model to assess interventions made several years ago. Field works included water and sediment sampling, along with in situ measurements of key environmental parameters. A composite index was developed to evaluate each basin’s environmental quality and find improvement opportunities. Two basins were classified as having good environmental conditions, while one (RT basin), showed average performance due to the discharge of untreated sewage from upstream sources, negatively affecting water and sediment quality. Despite these issues, all basins demonstrated potential for ecological and social improvement. The results indicate a favorable situation for local authorities implement effective, targeted actions. For broader impact, future interventions should be strategically planned, with careful attention to site selection and infrastructure sizing, as these factors are essential for long-term sustainability and community benefit.