## 5 Conclusions  
This study presents a structured methodology for evaluating the impact of SUDS implementation at catchment level in an evolving climate. This approach was found to be effective and applicable in a real-world context, as demonstrated by the Bari, Italy case study. This methodology can be applied to any small to medium-sized urban catchment area regardless of climate conditions, provided basic data on land use and precipitation are available.  
To support climate-resilient urban drainage planning, digital elevation models (DEMs) were integrated with a GIS-based application of the SCS-CN method. Using the curve number approach, the simulation estimates runoff volumes under various climate and land use scenarios. The key step was to compare these volumes with a historical baseline, which made it possible to quantify the storage capacity required to restore or maintain the area's natural hydrological balance. This insight can then be used to estimate the type and number of SUDS elements needed across different urban catchments, tailored to future climate projections.  
The results show that extreme storm volumes could increase 7-fold, while average storm volumes could increase 2.5-fold. This would pose a significant challenge to the current capacity of drainage infrastructure. Additionally, discharge peaks could exceed baseline values by up to 20% in some years, indicating a greater occurrence of extreme runoff events. Taken together, these findings suggest an increased risk of both flash floods and prolonged droughts in future decades, a risk that is further exacerbated by ongoing urbanisation.  
Based on these findings, we recommend:  
In practice: Prioritising the widespread implementation of SUDSs at the catchment scale, especially in areas undergoing intense urban development.  
Policy: Updating regulatory frameworks to assess SUDS performance based on their ability to restore natural hydrological balances, not just reduce peak flows.  
Research: Future land use changes must be integrated and the demand for SUDSs estimated to support decision-making.  
Resilience: Adopting scenario-based methodologies to improve long-term planning in the face of climate uncertainty, such as the one proposed.  
This methodology provides a strategic foundation to support sustainable urban water management and can be adapted to different territorial and climatic contexts.  
Conceptualization, S.Z., A.P.M. and M.T.G.-V.; methodology, S.Z., A.P.M. and M.T.G.-V.; validation, S.Z., A.P.M. and M.T.G.-V.; formal analysis, S.Z., A.P.M. and M.T.G.-V.; investigation, S.Z., A.P.M., R.S.V. and M.T.G.-V.; data curation, S.Z., A.P.M., R.S.V. and M.T.G.-V.; writing--original draft preparation, S.Z., A.P.M. and M.T.G.-V.; writing--review and editing, S.Z., A.P.M. and M.T.G.-V.; visualization, S.Z., A.P.M., R.S.V. and M.T.G.-V.; supervision, S.Z., A.P.M. and M.T.G.-V. All authors have read and agreed to the published version of the manuscript. This research project has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from the Universidad Politecnica de Madrid. Not applicable. Not applicable. Data Availability Statement: Data sharing is not applicable to this article as no datasets were generated or analyzed during the study. The authors declare no conflict of interest.