Since the 1950s, the Emilia-Romagna region has been characterized by significant land use transformations driven by urban expansion, infrastructural development, and the progressive reduction of traditional agricultural landscapes. These processes have contributed to the progressive intensification of soil sealing, significantly altering the hydrological balance and reducing the capacity of ecosystems to provide key regulating services. In particular, the extensive impermeabilization of land surfaces has amplified surface runoff, compromised groundwater recharge, and heightened the exposure of urban and peri-urban areas to hydraulic risks such as flooding and pluvial inundation. This study presents a diachronic analysis of land use change in Emilia-Romagna from the post-war period to the present, combining historical cartographic sources with regional open data. The research integrates spatial analysis and hydrological modelling in order to assess the implications of land cover transitions on both surface runoff dynamics and ecosystem services. Specifically, the workflow employed open-source GIS tools combined with modelling approaches such as InVEST and HEC-HMS, enabling the simulation of runoff behavior under different land cover scenarios. This methodological framework allows the quantification of changes in runoff volumes and the evaluation of their spatial distribution across watersheds of varying scales. Beyond the empirical findings, this study highlights the importance of spatial analysis and geospatial modelling as practical tools to support territorial planning. By combining historical and contemporary datasets within GIS environments, it is possible to identify vulnerable areas, assess the loss of ecosystem services, and explore alternative land management strategies. The results show that using spatially explicit approaches can help guide planning decisions, reduce further soil sealing, support sustainable land use, and make territories more resilient to flooding and climate impacts.