Analysing the Impact of Land Subsidence on the Flooding Risk: Evaluation Through InSAR and Modelling

Abstract Floods greatly impact human settlements in flood risk areas, such as floodplains and coastal lowlands, following heavy rainfall. The Alto Guadalentin valley, an orogenic tectonic depression, experiences extreme flash floods land subsidence due to groundwater withdrawal, rendering it one of Europe's fastest subsiding regions. In this study, we compared two 2D event models representing different scenarios for 1992 2016. To determine the flooded area water depth variations subsidence, Hydrologic Engineering Centre River Analysis System (HEC-RAS 2D) model was used simulate inundation by its tributaries. Synthetic aperture radar (SAR) satellite (ERS, ENVISAT, Cosmo-SkyMED) images were employed, along with interferometric SAR (InSAR) technique, calculate magnitude spatial distribution subsidence. By analysing accumulated distributions obtained from InSAR, original topography valley 2016 reconstructed. These digital surface (DSMs) then generate hydraulic models, simulating unsteady mode. results demonstrated significant changes elevation over 14-year period, a 2.04 km2 increase areas depths exceeding 0.7 m. findings utilized create map assess economic risk. data highlight crucial role determining providing valuable insights emergency management civil protection against future potential flooding events.