A new technical assessment confirms that the Caiara Park filtering garden in Recife, Brazil, continues to improve water quality more than two years after the completion of the GEF-6 Sustainable Cities project. Based on 14 monitoring campaigns conducted between 2024 and 2026, the report shows consistent reductions in organic matter, nitrogen, and suspended solids, demonstrating the long-term effectiveness of this nature-based solution. 

The assessment also highlights the successful transition of the system to local ownership, with dedicated municipal staff responsible for its operation and maintenance. While some operational challenges remain, including the introduction of fish into one of the treatment ponds by local residents, the filtering garden continues to serve as a successful example of green infrastructure in practice. The experience has already influenced similar initiatives in other Brazilian cities and is helping inform future national approaches to nature-based urban water management.