From Flood Mapping to Planning-Relevant Flood Intelligence: A Sentinel-1 SAR-Based Framework for Urban Planning and Climate Adaptation in Valencia, Spain

Flooding is among the most destructive natural hazards affecting urban environments worldwide, with its frequency and severity increasingly worsened by climate change and rapid urban expansion. This study presents an operational flood detection framework based on multi-temporal Sentinel-1 Synthetic Aperture Radar (SAR) imagery, applied to the severe flooding event in Valencia, Spain, in late 2024. The proposed workflow integrates pre- and post-event SAR acquisitions within a systematic processing chain that includes radiometric calibration, speckle noise reduction, and multi-temporal change detection. Flood delineation was achieved through threshold-based segmentation and post-classification refinement and independently validated against the Copernicus Emergency Management Service (EMS) rapid-mapping product, achieving an overall agreement of approximately 87%. The analysis identified an inundation extent of 4.96 km2, primarily in the western and northwestern sectors of Valencia. To enhance the practical relevance of the remote sensing results, this study develops a conceptual framework linking satellite-derived flood information with urban resilience planning and disaster risk management objectives. Rather than focusing solely on flood detection performance, the study emphasizes the translation of satellite-derived flood information into planning-relevant knowledge through measurable SDG-oriented planning indicators that support resilience-oriented urban governance. The framework demonstrates how spatial flood intelligence can support monitoring and decision-making processes related to Sustainable Development Goal (SDG) Targets 11.5, 11.b, and 13.1. By connecting satellite-based flood observations with policy-oriented urban planning frameworks, the proposed workflow provides evidence-based support for risk-sensitive land-use planning, infrastructure prioritization, evacuation planning, and post-disaster recovery while offering a transferable framework for municipal disaster risk management and urban resilience.