Effetti dell’impermeabilizzazione dei suoli sulle dinamiche idrologiche nel bacino del fiume Elsa in Toscana

The hydrological characteristics of the soil i.e. permeability, infiltration rate and water storage capacity, must be taken into account in the assessment of land use change impact on hydrological regime. Some human activities contribute to decrease absorption by infiltration of rainfall and consequently result in an increase in the volume and speed of runoff. A GIS-based hydrologic model (ArcSWAT) and elaboration of aerial photos (year 1954, 1978, 1988, 1996, 2007) are applied to assess the impacts of land use changes in the Elsa River Watershed upon flood volume measured at Castelfiorentino (FI). The analysis made it possible to quantify the effect of soil sealing upon surface runoff at watershed scale.