Rain gardens as sustainable solutions: advances in research in the world and the state of technology in Brazil

This article presents a systematic and critical analysis of rain gardens in both global and Brazilian contexts. A systematic literature review was conducted, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, with analysis of 43 articles published between 2014 and 2024, retrieved from the ScienceDirect, Web of Science, and SciELO databases. Quantitative synthesis indicates that hydrological efficiency is directly proportional to soil profile depth: optimized systems (> 1.2 m) achieve volume retention exceeding 80% (compared to 44% in shallow profiles), while infiltration rates reported in Brazil average 312 mm/h. Despite their proven effectiveness in pollutant removal and runoff control, the review identified clear gaps, including premature clogging caused by sediment accumulation, vegetation selection based on aesthetic criteria rather than root-mediated treatment capacity, and the inappropriate replication of design parameters from temperate to tropical climates. The study concludes that Brazil remains at an experimental validation stage, in contrast to the consolidated application of rain gardens in international public policies. The primary scientific contribution of this work lies in proposing a tropicalization agenda for engineering guidelines, emphasizing the need for long-term monitoring and the integration of modeling tools to achieve more robust technical outcomes.