The ICRA researcher Massimiliano Riva presented key activities of the European MULTISOURCE project (Grant Agreement No. 101003527) during the stakeholder engagement workshop held from March 11^th to 13^th, 2025, in Florianópolis, Brazil. Organized by the Federal University of Santa Catarina, the event brought together around 60 participants including representatives from universities, companies, and water utilities alongside eight project members who led various sessions and activities. In his first presentation, he shared results from the substrate selection process for the green wall system constructed at ICRA for greywater treatment and reuse. His second talk introduced Nat4Wat (https://nat4wat.icradev.cat), an online tool developed to help users select, compare, and explore nature-based solutions for water management.