Decision support systems for urban water scarcity: Gaps, barriers and pathways to integrate nature-based solutions – A systematic review

Urban water scarcity is intensifying due to rapid urbanization, climate change, and ageing infrastructure. In this context, Nature-based Solutions (NbS) offer potential to address urban water challenges by restoring ecological functions and delivering multiple co-benefits, yet their systematic integration into Decision Support Systems (DSS) remains limited. This study systematically reviews 50 peer-reviewed publications (2015–2025) to evaluate current knowledge, methodological gaps, and opportunities to integrate NbS within DSS for urban water scarcity. Results reveal that most DSS are predominantly focused on gray infrastructure, with limited capacity to model or evaluate NbS. Key barriers include technical and modeling constraints, governance and institutional fragmentation, socio-economic and participatory challenges, and geographical research imbalances. Identified opportunities include hybrid modeling approaches, sensor-supported monitoring methods, and application of digital twin technologies. In response to the identified gaps, the study proposes a conceptual decision-support framework integrating hydroinformatics, socio-ecological analysis, and stakeholder participation to strengthen urban water resilience.